Isn’t this exactly the type of thing that a market is designed to discover, which we’re seeing unfold right now?

Yes, maybe they’re building too many right now, who knows. It’s very likely that demand for computation will go up in the future, and EVs are also going to be consuming much more electricity, so all governments better start preparing for more (clean) electrical supply.

That’s all fine as long as the market covers all externalities. It doesn’t

Building data centers sounds like a good bet to make some money in the next decade or so.

That’s not the same as conceding that “everyone should get as much compute as they demand”.