It's a bigger issue in the US than other countries though. Not all countries value companies based on ridiculous amounts of speculation.

It's estimated that Anthropic's IPO will value them around $1.5 to 2 trillion even though their S-1 has 93 pages of risk factors, including that 20% of their revenue comes from their top 2 customers (and I guarantee that both would be looking into moving AI inference in-house), and they literally say that they may never be profitable:

We have a history of net losses and may not generate sufficient revenue to achieve or sustain profitability in the future

They also don't own any infrastructure like servers or racks - it's all rented.

Yet they're still going to have a large amount of people purchasing stock, based purely on vibes rather than actual data.

At least the S&P 500 still has some sense. Companies can only be added to the index if they've been trading for at least a year, and if they're profitable. They refused to change the rules for SpaceX, unlike Nasdaq-100 and Russell 1000.

Don't even get me started on Nvidia. There's no reason that a company that makes GPUs should be the most valuable company in the whole world. Actually they don't even make the GPUs - TSMC does.