sorry to jump in but technological trend generally goes through the FAD->maturity phrase, and users stay in this phrase because of FOMO (Fear of missing out) User experience isn’t factored into the equation until the technology is matured, which takes quiet a long time.
periodic payment incentives bidding and underground exchange. If coins are tied to the TTL then it becomes a capitalization game.
The solution for paying full nodes for storage can be dead simple - periodically (every x blocks), all nodes that provided old paid-for state (active full nodes) will receive a payment, equally split between them with the total calculated as, say, 50% of the total storage fees paid since the last counting. This would reward full nodes and incentivize users to run new ones, increasing security and performance. Only problem would be slightly more inflation, because to avoid it we’d have to either cut the mining/validation rewards or increase fees, which would neutralize the positive impact.