If I own a battleship, its turning radius is a meaningful metric. If I own a millionth of a battleship, I probably didn't buy in on the strength of its turning radius.

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?

There are equivalent cases in the meme stock world. GameStop, in particular, had an abnormally high market cap because of anomalous trading. If you hold onto it forever all you have is a dumb little videogame sales company worth a fraction of what you paid for it.

Meme stocks are quite interesting in that they are essentially like blockchain-driven asset bubbles, but without the blockchain. This has many advantages! It’s quite easy to trade stocks.

Well, if you literally owned every dollar in existence, those would become worthless pretty fast, too.

That’s right. And dollars don’t have a “market cap” either.

Nobody “invests” in literal dollars because they aren’t a productive investment either.

That's different from trying to imply that crypto is worthless and can't store value

This fact is actually news to a distressing number of people. Even on HN market cap is talked about like it's a giant corporate bank account. "Trillion dollar company can't do X" is an all too common refrain.