From the little I know you're trying to see SMT has the end of steem, No, it isn't, after SMT there will be still more development going on, many projects are still coming on board this steemit ship.
Now to your question, with Development Fund and Using other Blockchain, Steem can decide to use any of them, don't forget that this is a decentralised platform where voting has to be done.
Don't forget that Steem is yet to roll out so many plans to generate revenue or bring it to the table of the common man, those on the street, become a mainstream blockchain outlet with its fast transaction speed as an edge. By the time steemit becomes all this, trust, you wouldn't be asking this question anymore because business would have opened here and there and they'll surely be monetise.