

This above all things. The number of inputs required to build a microchips is insane. There are probably 2 to 3 thousand separate vendors who are part of this process all of which produce highly specialized products. Not to mention the fact that all silicon used to produce chips is currently mined in a single quarry in South Carolina.
China might be able to make a fab, but the inputs required to make chips are too diverse for any single nation to build 3 or 4 nm chips at scale by themselves.

It depends on the customer. Microsoft, Google, Amazon all have the revenue to carry the debts they are taking on. Oracle, Chat GPT, Musk and others are waay more sketchy.
The build out is going to take billions of dollars and these companies aren’t going to see a return for at least 5 years or more. The majors can carry that kind of debt load long term even if AI doesn’t pan out. Other businesses will struggle or go under if AI doesn’t bring the returns.
The next major movers will be companies that do a lot of IT business consulting like IBM. They are going to be busy helping non IT focused firms incorporate AI into their business model.
Finally if all these data centers pan out and the US keeps oscillating between shunning Renewables or Fossil fuels every time a new party comes to office we are going to have major problems with our energy infrastructure. Think energy bills as high as your mortgage within the next 5 years. Invest in utilities or energy companies and try to put solar and some kind of storage on your home.