So, you're actually asking two questions here, one of which has a more definitive answer than the other. For your first question, yes, the broad Kurgan Hypothesis is the most widely accepted answer for where the Proto Indo-European language and culture originated from, that being the steppes north of the Black Sea in modern Ukraine and southern Russia.

Recent genetic studies have added additional data for this, increasing the acceptance of the Kurgan Hypothesis.

But this is where the mainstream acceptance of Marija Gimbutas' work tends to end. For one, it is extremely difficult for us to make concrete conclusions about ancient societies, especially pre-literate ones that have left only fragmentary evidence. When we are only receiving bits and pieces, we tend to project onto them what we'd like or expect to see. Most mainstream archaeologists of this period acknowledge her work in helping to pioneer the Kurgan Hypothesis, but balk at accepting those conclusions about either culture.

For one, aside from lack of evidence, some of the evidence we do have points in a different directions. There is evidence of fortified settlements and buried weapons in pre-Indo-European Europe, as well as what seems to be male preference in burials, although again it's hard to draw firm conclusions with only fragmentary evidence.

So what does this tell us? Humans are trained by nature and culture to attempt to draw conclusions from the evidence they are presented with, and it can be hard to avoid the temptation to make guesses based on fragmentary evidence, particularly based on our pre-existing ideologies and biases.

In some sense, this is useful, as it gives us the drive to explore further and gather evidence to either support or refute those hypothesis. But we have to be careful not to make definitive statements when the evidence does not support it. The evidence is solid enough to have mainstream backing for the Kurgan Hypothesis, but we do not have enough evidence for the supposition of a replacement of a matriarchal, peaceful culture with a patriarchal, warlike culture.

While you wait, this is a pretty good previous reply on the general subject of Kurgan/Gimbutas: https://reddit.com/r/AskHistorians/comments/7iuut5/_/dr28i2u/?context=1

To add to everything said here (I took an entire class on this), Marija Gimbutas' theories, though on the right track as to the origin of Indo-European languages/people, reflect a personal bias and are highly problematic.

Personal bias:

Marija grew up in an independent Lithuania that was invaded, then annexed, by the Soviet Union. Anyone versed in Eastern European history knows about the perception of Russians and particularly Bolsheviks as "Asiatic hordes of barbarians" (read: Ukrainians today referring to Russian troops as "orcs").

Her vision of a peaceful, more female-focused, ancient Europe being overrun by warlike, Eastern barbarians would seem to involve a lot of her personal story. Of course, this suspicion would be less believable if she had evidence for her theories, but since she made wild leaps in her conclusions, we can't ignore her personal bias.

Which brings me to...her problematic analyses:

It is almost impossible to do history without written records. You are really doing anthropology or archaeology. Without written records, humanity's folklore, customs etc. of the 1850s would seem bizarre to you.

Now multiply that difference by thousands. So much time passed without us knowing anything about religion and culture. Entire major religions may have risen and fallen in this period. It's easy to guess what people ate, what technologies they had, but anything related to societal structure is near impossible.

Back to Marija. If you read her books, she exhibits confirmation bias everywhere. She believed that the feminine was deified in old Europe and saw its symbols everywhere. If I recall correctly, she claimed that bird figurines were obvious representations of a female deity. But why?

She also claims the chevron is a symbol of the vulva, hence always represents the feminine. But why? If we follow Occam's Razor, couldn't a chevron just have been a cool decorative motif? The way that someone today puts one on a souped up sports car?

And this happens over and over in her books, so unfortunately its hard to take her seriously most of the time.

Finally, though she may have proposed the Kurgan hypothesis, archaeologists and linguists really did the leg work here. For example, they reconstructed the proto-Indo-European language, identified non-borrowed words for certain plants that had very defined growing ranges, and triangulated to a region basically on the Pontic Steppe or slightly east of it.

We assume they were patrilineal for a variety of reasons but mostly because they used the same word for "son" and "nephew".

Archaeologists excavated the very kurgans (burial mounds) found on the steppe and found horse burials and chariots, helping us understand that they were likely a horse-centered society, just as their steppe descendants were.

We know about their gods because we have records of Greek, Roman, Norse and Slavic pantheons while a major world religion practiced by a billion people today (Hinduism) originated from the Indo-European pantheon and has parallels to the pagan religions of Europe.

OH, and I almost forgot...many of the kurgan burials were of obviously high-ranking WOMEN (e.g. the Pazyryk kurgan). Also, the Greeks wrote in disgust about the Scythians of the Pontic Steppe fighting side-by-side with their women warriors, which was likely the genesis of the Amazon myth. This throws a major wrench in Gimbutas' theories!

In sum, I've watched recorded interviews with Gimbutas. She seems like the kind of lady you would love to have a cup of tea with, but I wouldnt put much faith in her historical analysis.

this happens to be my area of focus for the last couple years. the main idea is that- schismogenesis was at play here. as farming reached the neighbors of the people on the steppes (called the yamnaya culture by archaeologists) where farming wasn't really possible it had already been spreading from the levant for thousands of years. the agriculture-focused areas contained people who seem to have at least had female "deities" though they may not be what we think of as gods today. there was likely no centralized power structure yet in place. no standing armies, for example. not even much evidence of stratified living - no mansions or palaces that we could find. and no evidence of a state that we can determine. life seemed to be mostly peaceful punctuated by occasions of all-out destruction of some farming groups which the farmers would have had to deal with.

once farming could no longer spread across the vast steppe, the farmers instead of sending out new settlement groups, began to accumulate a surplus of food, people, animals and eventually stuff they produced like new styles of clay and art. this must have looked pretty enticing to their steppe neighbors who soon had so much stuff that they had to invent the wheel to carry it all around with them.

even if the yamnaya people who encountered these farmers were not patriarchal before contact, schismogenesis likely pushed them in that direction. it would have been a way to see themselves as different from the culture they were "invading". in a sense this difference is still with us today. it's easy to consider the opposite of this patriarchal, socially stratified and mostly unequal civilization of the last six thousand years as matriarchal and the "goddess" figurines seem to fit right into that analysis.

the thing to keep in mind though is that when Europe was mostly tribal groups for tens of thousands of years or so like in the america's, schismogenesis was still very much at play. just like in the Americas, there would have been intentional differences between tribes that bordered each other. we don't do things that way, that's THEM. so it's likely that at least some of these ancient European cultures were not matrilinear, we just don't have evidence like we do for the ones that had the "goddess" statues. perhaps there wasn't a need for props or they were made out of less durable materials. by the time of writing all of these tribal groups were already heavily influenced by their farming neighbors through trade and raiding.

it's likely that in our long pre-history groups of people lived in every possible combination of power structures, all of which would have left little evidence. it's probable that the invention of writing - and the way that the invention cemented culture - happened to coincide with certain iterations of it. even further back, if the yamnaya people had come across farmers that were already led by men, their power dynamic might have looked entirely different through schismogenesis.

lastly, nothing was really wiped out. the invaders we now know mostly integrated with local farming populations in various ways and even seemed to have "gone native" in some cases. Language can be more attributable to technology in the same way it is today and can't alone be used to determine cultural / genetic upheaval.

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"The Horse, the Wheel and Language" - David W Anthony

"Rapid radiation of the inner Indo-European languages: an advanced approach to Indo-European lexicostatistics" - Alexei S. Kassian, Mikhail Zhivlov et al

My humanities teacher claims that in prehistory, human society was generally matriarchal, b... with answers, questions, clarifications and the like written by u/OnlyDeanCanLayEggs u/Tiako (their second level comment talks about Marija Gimbuta) u/jschooltiger u/cleopatra_philopater u/RioAbajo u/Snapshot52. Note that one of the comments links outside the sub to r/AskAnthropology for additional reading (that will be of particular interest.