Now, people are trading tech stocks.

Basically, they fully price in expectations first, and then estimate how much revenue they can generate after capacity is maxed out.
Using an overestimated PE.
It’s really too optimistic.
Except for companies whose real products can perform and truly have moats, and who have pricing power—it’s fine.
For everyone else, once the market cools down, it’s a complete mess.
After Cisco, during the burst of the internet bubble.
Its revenue and profits kept increasing for ten years.
But the stock price never returned to what it was ten years ago.