I'm not sure.
I really do think Trump ran to troll the Republican Party, and is surprised that his obnoxious statements are resonating with so many of the inbred idiots in Jesus-Land who take him seriously.
But now with insulting the wives getting involved, i think it's become personal between him and Cruz.
I also think the GOP would rather Lose with Cruz than Win with Trump. Losing an election isn't that big of a deal to the Establishment. They'll still control the HOuse and the majority of the governorships. they might even retain the Senate, but if they don't, they'll get it back in 2018 because there will be some 25 Democratic seats up that cycle.
Also, a Cruz nomination followed by a Cruz loss would finally defang the stupid Conservative Refrain of "If you only nominated a REAL conservative, we'd win." Then the GOP can work on fixing the party's relationships with women, minorities and moderates.