Elon Musk will definitely make a behemoth out of Twitter if everything goes as planned. The social media part is already firmly in place. All that he'll have to do is leverage the large number of users to effectively build the other parts like finance, commerce etc. The problem is that since it's web 2.0, it'll be hard to tie all the pieces together. Whilst in web 3.0, the pieces are already tied together by default.