Yes, I think the current central hub has around 30GB or more of data. In my mind, this is the key limitation of Scuttlebutt, and I'm not sure it's fixable. Scuttlebutt is still worth learning from though.
It should be fixable by running your own personal "server" that is always online and has a good amount of storage, isn't it? The mobile app can sync to your personal server and fetch a limited history whenever needed.
I wasn't aware of that, I'd love a link to learn more about it. But anyway, the architecture supports a totally decentralized network; Manyverse supports p2p gossip, I think across a LAN, and maybe bluetooth as well?
This limitation is a feature :) Humans are only good at forming social relationships with a limited number of people (Dunbar's number). Scuttlebutt isn't designed to connect you with total strangers, only friends-of-friends-of-friends — a social network.