The dot-com was a bubble because investors pulled money and belief at the first sign of trouble.
The landscape has changed dramatically now. Investors and VCs have learnt if we stick with winners and growth companies, the payoffs are massive.
We also have more automatic, retail and foreign money flowing into the market. Buy the dip is a phenomenon that didn't exist at the scale it is now.
Pre-2015 if Big Money pulled out, the market was guaranteed to fail, but now retailers sometimes have longer views and belief (on people like Musk, Altman) than institutions and they continue to prop it.
So, it's foolish to apply 2000 parallels to now. Yes, history repeats, but doesn't with the exact time or price points