Fair points, but from what i know, those applications you mentioned remains centralized, ended up failure or don't use blockchain (only used as buzzword to raise hype).
IMO those applications can indeed be used decentralized.
The supply chain, for example.
You would be able to track the harvesting of the cottage, the transport via ships, the creation of yarn and finally the manufacturing of a shirt completely transparent.
There are multiple entities involved in such a process. And with a blockchain tracking all of these steps, there would basically be no central authority.
Yet, there is not a single project which does that.
Anything one can find at the moment, indeed just uses blockchain as a buzzword. But i am confident that we can have several applications backed by a blockchain in the future which have absolutely nothing to do with cryptocurrencies.
Look, decentralization and/or trustlessness does not mean replication or resisting single physical point of failure. To keep a system truly decentralized you need to let it be open and permissionless.
Now, for our open/permissionless/trustless/decentralized system either there is some value produced or not. If there is no value it would be rather a dummy absurd system with no purpose and no utility and if we are dealing with some kind of value we need to keep our system secure against adversaries and spammers.
But adversaries are complex entities that follow their goals with very sophisticated patterns of behavior. So we need game theory and incentive system: a cryptocurrency token is born, congrats.
It is possible to have smart contracts and/hence an unlimited number of applications supported by cryptocurrencies but blockchain alone? Of course not! It would be just a nightmare! Just forget about it.