Pyramid scheme
It's basically a pyramid scheme. Or the Martingale betting scheme (double your stake after every loss, you'll eventually win and recover your sum of losses). All valid schemes assuming there's infinite room for growth, which there isn't.
Eventually, Amazon will need to generate sustainable profit/growth in order to stop collapsing under its own weight. Or bubble, if you will.
Of course, Bezos and his many billions will be nowhere near it when that happens.