Earlier quoted context omitted.
EDIT: Thanks for this comment — I edited the original for clarity. I'm talking about crypto as in Ethereum, which are designed to resist centralization. HN wrongly thinks of crypto as a financial system (which it can do, for good and bad reasons thanks to its permissionlessness), instead of a family of methods for making composable, decentralized protocols with built-in economics (blockchains).
But why do these protocols need built-in economics? No user is going to want to have a wallet that slowly drains as they use the web -- it's just not convenient and will be thoroughly rejected by the mainstream. Compare this to something like torrenting - people give, people take. Sure, indexing is centralized, but once you have the index, it's all p2p. That's the direction decentralization should be taking, instead…
You don't need the mainstream, you just need the cool kids. The mainstream will follow---or not.
As for why anyone would want this, there is a very compelling reason---no ads.