"GPU compute powering crypto for the last decade..." I keep hearing this lately. Also, that GPU compute has been re-purposed from crypto to AI. I had the impression that crypto was powered by ASICs for the last... many years. And that was why GPU mining (let alone CPU mining) was not profitable
Major cryptocurrencies are based on Proof of Work or Proof of Stake. There are other consensus algorithms.
https://en.wikipedia.org/wiki/Scrypt#Introduction
scrypt has been introduced to stave off ASIC and FPGA solutions.