Nvidia currently has ~75% margins and ~90% growth. If either of those nobs get turned down slightly, their valuation can tank.
Which is what happened.
If Nvidia's 10-year growth forecast went from ~40% per year (29x in 10 years) to ~30% per year (14x in 10 years) - that's a 50% smaller future company you're expecting.
It's still great for Nvidia. It's just LESS great than people thought before, which means their market cap comes down a ton.
That's what you're all forgetting.