I am using Hive as an accumulation for my wallets as well, beyond the simple Hive Blog. I think that Hive has great potential and we should focus now on onboarding new users, using Hive for its different use-cases, widening the audience.
Anyway, for the moment your calculation seems pretty optimistic (even utopistic) but who knows. Seeing the sudden centralization of Ethereum, we never know what is going to happen!