I personally think that Jeb Bush should have run for senate but that's just me. I'm sure if he had run he could have beat Nelson by 10-12% considering Jebs overall popularity. Taxes in the state have been kept rather low and overall the economy is cranking better then the rest of the country and unemployment is lower then the national number. Maybe Jeb is saving himself for a presidential run? I don't know but I think that's likely.
I am aware that Jeb Bush has refused to run for president, but I do not recall him ruling out running for any other office -though perhaps you have a better memory than I do. And assuming he has ruled out running for any future office, he still has until May 12 (the federal filing deadline) to change his mind. The fact that Katherine Harris is floundering must be making some impression on him.....