Wall street undervalued Google even on day one (IPO). Bezos has said that some of the times the stock had been doing the worst were when the company was doing great.

So, to help you understand how they can be true: market cap is governed by something other than what a business is worth.

As an aside, here's a fun article that embarrasses wall street. [0]

[0] https://www.nbcnews.com/id/wbna15536386