No one can predict how someone will act when in office (well, Zero is an exception cause he was a devout Marxist). But Reagan went along with a tax increase, Bush folded on bailouts, etc. We CAN look at the predictions by Erickson and the other pundits as listed above. So far they have all been horribly wrong. Most of them, even if they have to admit it, really say it like, "Yeah, but we're only wrong because you voters are stupid." I went through this with Jim Geraghty of NRO---usually a pretty fair and smart guy. But the NRO crowd is 100% Bushie, and hate Trump. Of all things, THEY try to claim that Trump "isn't conservative enough."
My point is not to again debate Trump's conservatism or lack thereof, but to at least suggest that with a track record of the pundits about Trump, I'd take him in a bet any day.
.....and this is like air traffic control.....an insurgent candidacy must defy gravity 100% of the time. One slip and it's normally over. And by slip, I mean a slip that gets traction. I think he's made about 3 of those so far, and at some point, one will get traction IMO.