Bush wins. I don't even know who Paul Simon is.
Well, that's certainly a good enough reason for me.
Seriously... I doubt that Simon would have won. He was seen during the nomination campaign as being more liberal than Dukakis, and the national ideology was still pretty far to the right in '88. He wasn't very telegenic either, although I could see him doing quite well in the debates, where his calm and reasoned demeanor might contrast well with Bush I's Liberace voice and nervous tics. Provided that he ran a better campaign than Dukakis, and I can't imagine him (or anyone else) running a worse one, he would have done better in the PV and EV, though not well enough to win.