Maybe blockchain technologies go the way of the car phone. That is, they were novel and useful for a time but other advancements rendered them obsolete. Or, may

Maybe blockchain technologies go the way of the car phone. That is, they were novel and useful for a time but other advancements rendered them obsolete. Or, maybe future fiction doesn't need to account for every possible future technology and instead will feature fictional things/ideas the author simply thinks is cool/interesting to play with.