I'm almost tempted to say that you're wrong on both accounts, that vapourware doesn't get prolonged attention and that blockchain is pure vapourware.
But to focus on the first one: homeopathy was invented in 1796 and is still going strong, with national health systems having committees on how to deal with it, even some accredited universities offer courses at least covering homeopathy too. And that's despite its impressive 200-year record of complete absence of evidence that it has any effects. Various forms of alchemy were complete vapourware and yet courted and sponsored by monarchs. Also in our enlightened days there are people building (and crashing with) rockets to 'prove' that our earth is flat, newspapers print horoscopes and the previous US president touted things worse than vapourware as cures for a global pandemic. Looking at the history of ideas, I'd almost say we're living the exception, with so many ideas that actually work.
Re blockchain, if you take it to include the whole "crypto" (web3) space, it's gone from implementing papers from 20+ years prior (Byzantine Fault Tolerance) to papers from a few years ago (Zero Knowledge Proofs). It's had societal impact in creatig a global subculture of crypto 'bros' that donated (at least) $100m to Ukraine (and also to other causes like India Covid relief), and created outlandish investment returns for early adopters.
In terms of the tech or what it can do, blockchains allow trustless peer-to-peer transactions, and smart contracts allow making trustless binding future commitments. The latter is no small feat if you consider that the difference between cooperative and non-cooperative game theory is precisely the ability to make binding commitments (think of what the rational action in a prisoner's dilemma would be if you had a third move of entering a smart contract that plays the cooperative move on behalf of both parties if and only if both sides committed, and defects on behalf of that player if only one committed - would you still choose to defect unilaterally, or would you rather enter the contract?). You might say that we already have a legal system and courts that can enforce commitments, but in reality not everyone on this planet has equal access to such a system. Smart contracts will always be "beneath" the courts (as in, if someone wants to renege on their commitment, eg because the contract didn't do what they thought it would, the courts will always have the final word), but they can remove a lot of friction, especially for smaller projects and if parties are in muliple countries.