Given the way Cruz was marketed to the GOP masses, and the way his background was kept hidden, I think the GOPe was trying to copy the Dem’s 2008 Obama strategy by the book.
It probably would have worked, too, except for three things: 1) Trump, 2) the fact that Cruz is such an awful campaigner on the national stage; and 3) Cruz’s nasty personality bubbled up as the campaign grind wore on, and people (except for his die-hard supporters) saw past the Potemkin Village that was his campaign persona, and recoiled in horror.