Yes but if you buy all his stocks you get a big chunk of Amazon, the company. If you buy up the rest of it held by other people you’d have all of the warehouses, brand equity, employment contracts, software, computers, and inventory. All of it.

The market cap has some relationship (not 1:1 but strongly correlated) to what you’d have to pay to get all that stuff. And if you’d had that stuff you’d be rich. Because those things, together, are intensely valuable and capable of producing cash flow.

By contrast if you bought up 100% of a specific cryptocurrency you’d have nothing. Like absolutely nothing at all.

This is literal. Do a thought experiment and decide what would happen if somehow you suddenly took possession of every single Bitcoin in existence and nobody else could get one without you giving it to them. What, exactly, do you think would happen then?