Every user of the network has to provide some storage for the network itself. If there's not enough storage to safely store your new content on the network as highly available, the network would just say sorry, can't do right now, please wait on the line while we get new storage (users).
Sure, it would need some massive network effect to work at scale, but we have now, what, billions of devices connected to Internet? That ought to be enough.
I never really understood this current "decentralized" tech. Decentralized hashes with centralized gate keepers, and mixed with "old school SPOF tech", e.x. the VPS's that store the actual content. wat.
edit: 10GB per device/user and 1 billion devices. That's 10 exabytes. https://www.wolframalpha.com/input/?i=10GB+*+1+billion