Today I thought of a question: the future belongs to AI, so why are there still sharp drops during the surge of AI industry chain stocks?

Probably because the market is adjusting the gains to match its quarterly revenue or expected revenue over the next few years.
It's like riding a horse on the prairie. Although the horse is galloping wildly, in reality, you are constantly pulling the reins back and forth to regulate its pace during the run, and when it gets tired, you have to give it some grass to eat.