The current value of Twitter is not in it’s technology, it’s in it’s userbase. You could write a better engine to do what they do, but you can’t convince enough people to use it.
Your suggestion to decentralize essentially has them giving credibility to external sites (who licence their engine) at a cost of what they value most (their users). Once I’m buying t-server from them, a new startup can compete on features..<p>I’m sure there are lots of good ways for Twitter to make money, but I don’t think that diluting their user base is one of them..