I think it's more likely he pushes for one of the other two big contenders (Rubio or Cruz) to be drafted. Or he could go totally rogue and run an independent campaign just to screw Trump over. And then maybe Sanders does the same. And then that opens a door for Bloomberg's independent run. And then after the ensuing chaos does damage to both parties, we finally get some real discussion going about instituting instant runoff voting.
One can always hope.
For many of us looking at it from the outside the American system is quite interesting and also a bit mysterious. Mitt Romney gave a speech today where he seemed to try to destroy Trump. So a question that comes to mind is could Romney be drafted at the Republican convention ?