I'm equally convinced - and I suspect I disagree with most HNers here - that there are also some problems for which blockchains are the only solution - they just don't work with centralized data stores, mostly because nobody would trust a single entity to manage that data store. Google isn't even looking for those problems. In general, Google does not look for problems, it takes problems that everybody knows about and looks for solutions. There are thousands of entrepreneurs in the cryptoverse who are looking for those problems.
There was a time, early in its history, where Google was willing to take a solution - download the web and keep only the links - and then find the problem (search) for which it was the solution. And then they leveraged that solution into all sorts of other problems - webmail, navigation & directions, news, academic papers, video, etc. But the thing is that this is a risky business: most solutions in search of a problem don't actually solve anything, so the time spent solving them is wasted.
Name a single actual problem that is only solved by the blockchain.
I'm not sure if you're being facetious, but assuming Amazon is a member of "FAANG": https://aws.amazon.com/managed-blockchain/. Does that count?
b) 'Wasting time' is a part of research. If you never fail, you're missing opportunities. That said, you pick your failures with the hope of getting the right kinds of wins... which brings us to...
c) Giant centralized cloud-based businesses have giant centralized and for-the-most-part trusted datastores. There's no reason to use a blockchain if a standard distributed database suits your needs. From where I sit, blockchains are mainly a solution in search of a problem.
(and just imagine the press cycles if a FAANG company rolled out a blockchain, and thus burnt god-knows how much coal bringing it mainstream...)