A large number of companies failed in the dotcom crash, but the founders did pretty well if they'd made it to an exit event. Don't forget that it was a stock market bubble imploding. The founders and early employees had already sold shares in the IPOs that put the companies on exchanges. It was the investors who bought stock that lost money.

The after effects were that it was virtually impossible to raise capital for a while afterwards, so the next round of founders struggled. But then interest rates went to practically zero and money got cheap so it was all good.