This is wrong. If Amazon earns $1bn extra profit the market cap of the companies shares could/should increase at least $1bn (depending on how it was made, and any future prospects for repeating the win).

However, no money is transferred to shareholders unless Amazon do a buy back or issue a dividend, it's just a revaluation. If those shareholders starting selling, only market forces (belief in Amazon) keep the price up. Shareholders can't demand their share of that $1bn in most cases, short of suing the company.

Stocks can and do trade below book value. Companies with net $1bn in the bank can have a market cap below $1bn in inefficient markets.