As someone who grew up in the Alps I will try my best to answer this question. Right at the start: Many of those "powerhouses" you describe only recently (in historic dimensions) became so. The bavarian Alps and the austrian Alps very long were anything but rich and economically powerful. They were among the poorest regions of Europe. A lot of this changed only during the 20th century and in the case of Bavaria for example even later, only late in the second half of the 20th century.

Another caveat: Many places you list aren't in the Alps per se, but rather in the regions that surround the Alps. Munich and Milan (BMW and FIAT respectively) are close to the mountains, but not in them, which makes a lot of difference. Big parts of Bavaria, which aren't close to Munich are also not very economically strong. It is mostly the area directly close to those big cities which is well off.

There are a couple of things however, that give all of those regions you mentioned economic advantages.

These are:

• being on important transit and trade routes.

• being idealized in the 19th and 20th century as holiday spots.

• a certain willingness to trade on both things equally, to the point of self-exploitation.

Historically, transit across the Alps was always important. The route Munich - Venice for example is centuries old and has always been very important. Roman roads to the bavarian provinces had to cross the alps. Modern roads follow those roman roads almost perfectly. It's the same for many other places in and around the alps. Crossing the alps was necessary to get to the rich italian cities on the adriatic and the mediterrenean coast. Venice and Genoa are the ones that immediately spring to mind.

Crossing the alps however was a daunting task for a long time, even all the way up to the middle of the 19th century. They had to be crossed on foot or by using carriages. This made travel across nigh impossible in winter and hard and ardous in spring, summer and fall. So life in one of the villages in the alps was very much the backwater-experience you would expect. Life was very hard and often dangerous since weather phenomena tend to be stronger in the mountains. Anyone who has experienced a thunderstorm while in the mountains knows what I'm talking about.

The soil in the mountains is also not suitable to farming. That's why farmers in the mountains tend to farm animals, not crops, even today. Heavy weather, poor soil - basically: Life in the mountains was always close to being unsustainable. People had to be inventive, and try to make money however possible. Woodcarving became a trade that was one way to earn money. Those long winters in the mountains gave you plenty of time to hone your carving skills and wood was in ample supply. There are records of bavarian woodcarvers carving altars in the 1500's and 1600's. Most of this was by necesssity. Many people living in the alps were so poor they sent their children basically into slavery in the cities in Baden, Württemberg and parts of Bavaria. These so called "Schwabenkinder" existed all the way into the 20th century.

So that's the reality at the turn of the 19th to the 20th century for many of those spots, especially in the northern Alps.

So what changed?

Trains, tunnels and roads.

As soon as crossing the alps become easier by way of modern technology, they turned from inaccessible regions to a knot on which trade through europe turned. 5 countries border on each other in this region. Three of those were large countries which had long established trade with each other: Germany, France and Italy. Switzerland sat right in between of them. At the same time, at the turn from the 19th to the 20th century, the progressing industrialisation all over Europe turned the Alps into a bucolic vision of a simpler and better life. The clearest example of this are the "Heidi"-novels by Johanna Spyri, which portray life in the alps as wholesome, healthy and ideal, instead of the constant struggle against the elements and poverty it was in reality. The picture many people have of the swiss alps is still very much influenced by this version of the alps. Even people in Japan and Turkey have heard of Heidi and the life she lead in the mountains. At the same time, other authors and artists followed this "back to nature" narrative and started to portray the Alps as a place where man could get properly in touch with nature and be humbled by the sheer size of the mountains and their majesty. Thomas Cook, the one of the travel company is one of those first tourists of the alps which told the world about them as a tourist destination. Since the alps where "multi-national"-no single country had a claim on all of the Alps- each country had it's own version. Austria and Switzerland always tried to market themselves as being the only country where you could experience the proper Alps, as opposed to for example Germany which only has mountains that reach barely 2900m in height. Yet every country you mention has a part of the Alps which it can call its own. "Heidi", "The sound of music" and a slew of german "Heimat-"movies all very much portray this image of the alps as a different world, where you're supposed to be able to connect with nature in a way you wouldn't in many parts of "flat Europe". Mountaineering was another side of this. Around the turn of the century, mountaineering was incredibly dangerous still, with equipment being much more prone to failure than today and the very real possibility of dying while climbing the summits of the alps. The "Matterhorn" wouldn't be as well known today if less people had died climbing it. To this day, each year at least one life is claimed by the mountain, which makes for a lot of mystery, adventure and good headlines. There is no bad PR. People want to see this mountain, which killed so many people, even if it is from a nice hotel on its feet.

So in summary: The regions weren't all that rich to start with. The change in travel through technology made the alps very accessible, in my opinion more accessible than any other mountainrange you mention. Each country in and around the alps had a vested interest in turning those poor areas into something else, so they were keen to exploit the early tourism and went full steam ahead. The romantic idealization of the Alps through novels like "Heidi" or through the adventures of the mountaineers functioned as great PR for this tourism and it still works today.

Sources: - sorry, mostly in German, as that is my native language and I'm not aware of english-language publications on these subjects.

Hartmann, Peter Claus: Bayerns Weg in die Gegenwart.

Dollinger, Hans: Bayern.

In both cases the economic history is the interesting part. Maybe someone else can weigh in with english/international sources.

Another great source to find out about life in the Alps:

Freilicht-Museum Glentleiten

It's a museum which collected whole farmhouses in the state they were left in, some very old ones. They regularly have great exhibitions on how people lived about a century ago or longer. They even offer workshops where you can try your own hand at old trades.

One personal aside: If the current crisis shows anything, it's how fragile the wealth of those regions is. Without tourism, many of the villages and towns in the alps would be bankrupt very soon and poverty would follow very quickly.

EDIT: I suck at formatting and spelling apparently. Had to try multiple times to get it looking passable. Added a passage about Munich and Milan which are close to the Alpine regions, but not "in" the mountains, which makes a lot of difference.

What were the effects of banking on Alpine (or "Alpine-adjacent") cities such as Munich, Milan, and (of course) Zurich? And over what period of time have banking had this effect?

I figure that, with Switzerland being neutral, reasonably stable, and centrally located, Zurich should make a fine place to go banking.