Yes, if you only invest in winners you'd be very rich! Which companies will be the winners though? Nobody knows.
What about the hundreds of losers that looked good right before the burst? My coworker retells a story where he dumped his life savings in dotcom companies that went to zero.
This is pretty much why the best financial advice for 99.99% of people is "stick with index funds".
Yeah you won't get extremely lucky and 200x your money because you bought NVidia a decade ago, but you also won't lose all your money because you bought Enron.
what? you mean that all my beenz.com stock is worth nil?? but it's an online currency! it's the future!
I'd start from a slightly more-charitable assumption which ends up in a slightly different "Hold up that's a little optimistic" territory.
1. Yes, if someone generally invested in "dot-com stocks" before that crash--covering both winners and losers--they might today have a surprising amount of (potential) dollars.
2. However much of that impressive-looking sum would be just because of 25-30 years in the market.
3. So we need to scale that "very rich" against someone putting the same money into an total-stock market index fund back then, which may not make it look nearly as impressive.