I'm sure most of the NeverTrumps would have relented if Trump himself had made the effort to be statesmanlike and Presidential. We all know that a Clinton Presidency will be wrong on the issues for conservatives. Those of us who have remained NeverTrump have known full well the price to paid, in terms of liberal policies and potential domination of the Supreme Court, of our opposition to Donald Trump.
We are, effectively, taking a stand against our own self interest. Now why in the world would we do that? It's because of Trump the man, Trump the erratic narcissist who simply won't grow up, who continues to engage in petty feuds and vendettas, threatening lawsuits and changing advisors like socks. Trump the naïve politician who falls into every trap the Dems set for him. Trump the demagogue who appeals to racialism no differently than Al Sharpton does. Trump the graceless who never apologizes for the insults and offense.
We look at Trump and conclude that, as bad as Hillary is, Trump is likely to be worse, a dangerous combination of inexperience and hubris who won't listen to counsel. He may be a fantastic real estate developer and father, but he lacks the temperament to be Commander in Chief.
In the end, the problem with Trump has been Trump himself and his refusal to change.