Have any of these storage coins figured out how to deal with the fact that it's easy to collude with yourself and efficiently pull off a Sybil attack to make it look like you're hosting lots of data?
For the Sybil attack, Sia uses proof of burn. Hosts provably burn money to demonstrate legitimacy. A Sybil attacker would have to spend real resources to appear as many hosts, and as the network grows, the required burn grows as well.
This means the host is guaranteed to get paid even if the renter disappears forever on week 2.
You can't set that up on Bitcoin.