I get your pessimism, but the same has been said about a lot of tech that did go on to change the world, just because a lot of people made a lot of noise about previous tech that failed to come to anything doesn't mean to say this is the same thing, it's completely different tech.
A lot of OpenAI's products are out in the real world and I use them everyday, I never touched Crypto, now maybe LLM's won't live up to the hype, but OpenAi's stuff is already been used in a lot of products, used by millions of users, even Spotify.
'A plausible sentence generator is just that: the next hype' - Maybe, but AI goes far beyond LLM as does the products OpenAI produces.