I'd say that the fact that no one agent has to is the basis of its success. In the end it isn't without its shortcomings, though, so I agree with your sentiment

I'd say that the fact that no one agent has to is the basis of its success. In the end it isn't without its shortcomings, though, so I agree with your sentiment in general. Either that, or something is used to incentivize the maintenance of the long tail of things, e.g. filecoin.