Super weird that you make such a clear cut distinction here. Both are federated systems that can work together or independently and neither have decentralized data storage.
Because email is decentralized everyone can communicate with other email servers and every email server can be owned by a person/community.
See, they’re essentially the same thing.
I think a federated system wouldn’t really help much for Storj though as storj isn’t about communication but rather access to your own data. Perhaps if you augment it with metadata caching it could at least ensure data is still accessible when your own satellite is down, but keep it read only because there would still need to be a single point of control over data. It’s not ideal, but it would be a step in the right direction. It would protect against data loss of Storj Labs goes under for example. You could even add methods to migrate control to a new satellite into the protocol to get full access again.
Satellites serving download coordination to customers based on cached metadata could get a small cut of the income for that download as compensation for their work, which would provide incentive to cache data. They shouldn’t get more than a small part as they’re not responsible for repair. I think something can be figured out with a certificate chain that a satellite is allowed to sign download orders for a specific customer, so storage nodes know they can trust they will be paid for that traffic.
Ps. I see some of this has been mentioned. I wrote this before reading the rest of the topic.