Or you can pin the NFT you bought yourself. You don't expect to buy a painting and then leave it wherever and have it always exist.

I think part of the sell of NFT's is precisely that you shouldn't have to manage the asset yourself. It would be quite odd that there would be an expectation that every holder of an NFT had to arrange preservation of it themselves, it seems a bit self defeating from what it's being sold as.

That's not what I know NFTs to be. I know them to be receipts/provenance logs, not art storage.

This is an important point that demonstrates two things.

First, that if you really care about what you're buying, you'll make sure what it references points to a content hash and not a URL, and you'll pin it yourself.

And second, that if you have to store the image yourself that you paid for a pointer to, you've wasted your money.

I'm a fan of cryptocurrency, cryptography underlying the internet, even the concept of a one of a kind, non fungible token is interesting and I see how it could be useful. But all this web3 stuff and in particular the hype with which the NFT concept is being marketed to sell useless shit are things I'm not a fan of.

People literally do buy art this way, it's in storage and bought and remains in the same storage. Of course buying it comes with the expectation of paying rent. But in this case of NFTs this is actually a hidden implementation detail rather than something addressed up front.