Also, it's worth noting that Cruz voters were more likely to vote for Trump in the general than were Kasich/Rubio voters. In the general, Trump won 98% of his own primary voters, 77% of Cruz's voters, 67% of Rubio's voters, and just 57% of Kasich's voters. Most of the remaining Cruz voters went for Gary Johnson or another candidate (I'm assuming McMullin?). Meanwhile, Clinton won a whopping 32% of Kasich's voters (compared to just 10% of Rubio's voters and 3% of Cruz's).
Well there was no way in hell Cruz supporters were going to bolt to Clinton. She had literally nothing in common with his platform like at all besides "never trump". But for the vast majority of Cruz voters knew that while trump was far from the ideal choice, he was plain and simple the closer of the two, and therefore seemed to be the option to go with