interesting - reminds me of what meteor attempted with its data protocol.
As with any stateful solution it has problems scaling. I'm not sure LiveView is the right answer.
Memory might become an issue though, I suppose. Every user's state will be in-memory in 'their' LiveView process.
On the other hand, there's much less state needed than with a client-side solution like React, because it can be very quickly fetched when needed.