I may have missed it, but I didn't see any mention of data duplication. How resiliant would this system be to N nodes suddenly disappearing? What percentage of the network could go down and still allow you to reliably retrieve your data?
To affect a file large amount of nodes would have to go down simultaneously. Again the user has control over this N = 1 - Data failure N = 3 - Good for just average cases. Probably still Sybil attacks possible if the have 20-30% of the network. N = 100 - Are you expecting tactical nuclear strikes or acts of God?
Cool thing is if you increase redundancy to a large number Storj starts to act like a CDN or torrent network. But thats outside the scope of your question.
Are you not?
Because VPS providers profit margins are so high vs a typical home user, they will be eventually replaced, but it allows Storj to scale pretty quickly using the traditional cloud as network nodes.