The problem is that most such schemes end up requiring both a blockchain and an established centralized authority, because the blockchain doesn't actually solve the problem its meant to solve (since the only problem it solves is distributed consensus on the order of events in the blockchain - no more, no less).
I think it does, because of its complexity, it's more of a set of technologies than just a software solution. Preventing double-spend is just the main use, however in order to do this a whole game-theoretical economic/technological system is required and that also solves and/or creates other problems. For cryptocurrencies, DAOs and similar systems economics is a security concern (wrong incentives will make it possible for an someone to game and/or break the system).
The point is that blockchains don't provide you with anything other than that "main use". For any other kind of feature you need to add something else - and if you're adding a centralized trusted authority (which is by far the easiest way to do anything), then you can get rid of the blockchain altogether.
