That's fair. Maybe someday there will be a regulated, fair, and secure market. I will admit that it's not entirely fair to judge a concept based on early adopters, which tend to be idealists and criminals for the obvious reason that it's just not on society's radar yet.
However, despite the potential social/tech merits, I do want to assert one reason that I personally believe blockchain is unsustainable in widespread use: Energy use. "Mining" for crypto entails billions of billions of repeated useless calculations that do nothing but waste electricity in the hope of obtaining the rights to the next batch of coins. Even when you put aside currency as a use for blockchain, every transaction requires that the ledger be propagated throughout the network, which, instead of being logged a few times in a database, has to be logged in literally every user's device. That may sound inconsequential, but make no mistake, it uses a massive amount of electricity relative to traditional, centrally-serviced transactions. Electricity is cheap, but it's not free, and we shouldn't treat it like it is.
When electricity is freely available to everyone and has zero environmental consequences, I may change my tune.