As someone who has also been following those projects, I actually think this is a great application for cryptocurrency. (Not necessarily blockchain; I'm pretty sure Maidsafe actually doesn't use a blockchain.)

The idea of a trustless, fully decentralized, scalable, redundant, anonymous storage market is pretty alluring, and I see no reason why it's not entirely achievable with current cryptocurrency technology.

I agree many of those platforms have issues, but from what I can tell those issues are mostly a result of the system's immaturity; not an inherent flaw in the idea of a decentralized storage system itself.

Here's my current take on each:

* Filecoin - Doesn't exist (yet). It's just a whitepaper; no actual software.

* Storj - Not actually decentralized (as currently implemented). Users need to go through a federated service (of which only one currently exists; the one run by the creators of Storj) to actually store their files.

* Maidsafe - I'm actually not sure. The developers of Maidsafe seem to be working on much, much more than just file storage, which means the project is very complex. In any case, the software is still too immature to actually use for real.

* Sia - This is actually pretty promising. A couple weeks ago I managed to upload and store a few GB worth of files on Sia for about $2/TB-month. Going to try using it for my online backups via Duplicati once I get a chance to play with it more. The core software is still pretty clunky though, and not recommended for production use.

* TRON - I have no idea. I haven't looked into it.

About Maidsafe: their goal is to build a new descentralised internet, and I think they still are in the alpha phase with testing on a big swarm of VPS's. It is a moonshot project, with all its pros and cons. And yeah, they use Rust ;)

Filecoin hasn't launched yet. None of the others have much traction, but I'm not sure I'd call them failed yet.

TRON is just garbage though.