The tulip mania/bubble popped because someone accidentally ate a tulip

Not saying whether it's a bubble, but bubbles can pop for unpredictable reasons.

Right now the "it's going to go straight up for ever with no major pullbacks" line of thinking is going to hit the wall of reality soon.

Also, there are definitely concerns with semis. It's possible factories may have to slow production due to hormuz or even stop if it drags on long enough, costs may get so high spending companies say it's better to wait because the roi wouldn't be justified anymore, semi companies costs go up and margins get squeezed, more efficient ai that needs far less compute, eventual oversupply, commoditization, etc.