Maybe bitcoin and crypto are not valuable... but the mathematical ideas of blockchain are, after the bubble dies they'll just become boring pieces of crucial infrastructure that sit in the background but they'll be there, it's the only way to ensure data auditing and integrity, and sooner or later people will be ok with paying 10x or 100x storage and compute costs for auditable integrity.
It's just that the real deal insight behind blockchain is not sexy and not something that's easy to make money from...