To say this has nothing to do with blockchain is like saying RADAR had nothing to do with war. Yes, people knew Maxwell's equations prior, i.e. "knew the proofs," w.r.t. ZKP but it has only really been developed much later, during the war.
The whole field of zero-knowledge mathematics was, if not non-existent, but certainly marginalised, before the crypto investment has hit the scene; this is facts. Yes, Shamir et al. go back to 90s, but it's a far-cry from zkSNARK, zkVM stuff we have nowadays. It has also popularized many applications, like provable auctions (see kyber[1] library in Go as nice starting point...) and opened the door to homomorphic stuff.