Actually, there's a very interesting trend in the poll numbers, when analyzed by age group:
Trump did BEST (of his numbers), by a small margin, in the 18-29 age group (37%), and did worst in the 65+ age group (29%).
Conversely, Bush, Christie, & Kasich (the "most" establishment candidates?) did worst in the 18-29 age group, and generally best in the 65+ age group. (Christie's best (9%) was in the 45-64 age group, one point above his 65+ result.)
I would surmise that "well off" voters who are more-or-less "comfortably set" and "comfortable" with their economic circumstance are leaning toward the establishment candidates, and looking for a "steady hand" manager type. Indeed, except for Bush's performance with the under $30k/yr group, the income numbers tend to bear this out. (Possibly Bush does well under $30k/yr group because of his name recognition and / or that group was most easily swayed by his huge ad campaign?)
Put another way, I'd say many Trump voters think questions about his ideology are secondary: They believe the system is rigged, and want someone to make drastic changes & give them a shot at working for a better life. GOPe voters tend to want more of a "manager".
"It's my economy, stupid."
Thoughts?
Well, if we look at this in purely mathematical terms, no candidate in a nine person race should get more than 11% of any demographic.
The fact that Trump got 29% of the over 65s, is impressive. That’s just under three times what he should be expected to receive.