IMO Amazon and most other dotcom companies were waaay overvalued at the tail end of the dotcom boom and many companies with hefty valuations from those days do

IMO Amazon and most other dotcom companies were waaay overvalued at the tail end of the dotcom boom and many companies with hefty valuations from those days do not exist today. What made Amazon survive (and achieve valuations way in excess of those in 1999) was not the fact that it had something super valuable then, but that it relentlessly innovated, stayed flexible (an online bookstore offering a computing cloud services, what a weird idea) and executed well enough. And had enough money and controlled costs well enough to reach profitability. For every Amazon there are hundreds of Enrons and WorldComs.