'Jitney' is just a term for a vehicle for hire, like taxi or cab, not (as far as I'm aware) a term for a specific company.
So that's the first thing to be aware of; the jitney phenomenon in the early twentieth century wasn't companies organizing drivers into a service like Uber and Lyft do, it was drivers offering their services freelance.
It was basically a spontaneous phenomenon that sprang up first in California around 1914. The two factors I've seen cited for its rise are a massive increase in the number of cars over the preceding few years, and a recession. A significant number of people had cars but no jobs, which was a combination that had simply never occurred before.
As for the street car companies, they absolutely hit jitneys as hard as they could, often with support from city governments. In a lot of cities, private light rail concerns were entwined pretty heavily with local government, with streetcar profits being used for things like park maintenance. In other places, entire neighborhoods had been built by streetcar operators on spec, essentially acting like real estate speculators in the attempt to create a guaranteed customer base.
Street cars weren't the only pressure, though. We're talking about 1914-1920—cars were a very new thing. Some states required licenses, but there was no such thing as a road test yet. (A few states had written exams.) Auto insurance wasn't what you'd call common, let alone mandatory. And traffic signals... yeah.
So, imagine for a moment groups of uninsured men who may or may not have any real idea of how to operate a car roaming around cities without much in the way of traffic controls, aggressively picking up fares. You can see, I imagine, where opposition to the phenomenon might come from more than just streetcar companies. Realistically, no one who doesn't rely on jitneys is going to like them very much.
What actually killed the phenomenon varies from place to place. Some cities just banned them outright, others basically regulated them into oblivion with insurance requirements and the like. In New York City, the traditional refusal of the yellow cabs to leave Manhattan has meant that unlicensed freelancers never went away at all, and even now you can hail an unlicensed 'gypsy cab' in the outer boroughs. (The City has recently taken steps to expand licensed cab service beyond the profitable bits of Manhattan, but that falls under the 20-year-rule.)
If you're interested in early twentieth century US civic transportation, I would suggest taking a look at Kenneth Jackson's Crabgrass Frontier, which is nominally about the rise of suburbs in the US, but which necessarily deals very heavily with transportation, including the various shenanigans of light rail concerns and their interplay the automobile.
Hey all. Just a couple quick reminders:
TED talks are also to be avoided, even if it is the CEO of Uber.
Wikipedia too.
Let's try to keep in mind where we're having this conversation, and be sure to keep answers up to a standard that you know won't result in an immediate removal.
Thanks!
What makes Uber Uber in your mind here? As in, distinct from a taxi that can be called or hailed?
Without the smartphone/GPS/autopay aspects, it's hard to imagine a service being similar to Uber 100 years ago.