Because the intersection of the stated goals and the actual goals is essentially empty. The actual goal isn't to be useful, it's to make the early adopters rich.
There's simply a real discovery problem, because of the aforementioned gold rush. Participants have too many incentives to bury accurate information that speaks against their investment, spread misinformation that embellishes it, suppress information about projects they want to invest in but didn't yet, ...
The argumentation of typical crypto fan is like the motte and bailey fallacy mounted on a helicopter rotor, constantly oscillating between some noble goals (decentralisation, freedom, privacy, anti-inflation, anti-fractional banking) and the "have fun staying poor" snark.