Trump's brings a private sector mentality to the campaign. He is wealthy because he dropped his mistakes like hot rocks (failed airlines, casinos, mortgage, vodka, university, steaks, etc etc) often with bankruptcy absolution. No looking back. On the campaign trail, he is shameless in just saying stuff and changing later. Gets a pass. He has no personal history other than the one he tells.
Public office is different. Every mistake is a permanent club for the opposition and any change in explanation a lie, particularly when repeated for decades.
Given those advantages, which are working here, Trump should be the odds on favorite.