With all due respect I think you're wrong: Trump supporters have never been fooled.
I think they know EXACTLY what they're getting. They just dont care because they believe the other candidates are even worse.
I have close friends who are Trump supporters. They've bought into his cocky NY successful businessman who makes deals schtick hook, line, and sinker. I even have bets with all of them on what he does in November if he's the nominee.
They think Trump is really going to do something, but all he's doing is feeding his own ego and seeing how long he can keep this charade up.