Here is an interesting article: Trump got the most GOP votes ever — both for and against him — and other fun facts
Over 12 million for and over 16 million against.
Here's another from 538: Primary Turnout Means Nothing For The General Election
Primary Turnout Means Nothing For The General Election | FiveThirtyEight
Scroll down to the table and you will find out that in six modern era presidential elections, the party who received the most primary votes won the general election three times. The party which received the lowest primary votes also won the general election three times. So turn out in the primaries means nothing in the general, all it means is one party had a more interesting and exciting race than the other party.
The bottom line, don't put much stock in primary vote totals. I doubt Trump will drop out before the election. But then again, Trump does what he wants to do and he does it his way, no one else's.
I would imagine unless Trump straightens up and begins to run a campaign to enlarge his base, that conspiracy theory will be brought up more and more. With everything Trump has done since he cinched the nomination, most of it off the wall and wrong, one begins to think he can't be that dumb politically. Then asks the question, is he doing it on purpose to ensure a Hillary win? I had a Republican country chairman tell me that way back in July or August of 2015. He believed it back then, I laughed. Now I just don't know. So that conspiracy theory has been around at least that long.