In the late 1990s, the phrase the “new economy” was coined in reaction to Internet companies that seemed to defy all the normal laws of business physics.

They could raise massive sums of capital, and go public for billions of dollars with no revenues a year later. John Doerr famously called it the largest “legal creation of wealth in human history.”

It went on long enough, and the valuations and even actual liquid returns became so huge, that even the cynics came to believe somehow the math would just work...