Romney set himself up to lose the last election. Trump has not done so.
Here’s a 2012 video by Bill Whittle. He argues that among the reasons Romney did not win the election is that he apologized for, rather than articulate and praise, what (should have been) Republican principles.
Trump does not apologize for his business successes; he is proud of them and emphasizes them.
Trump should watch and listen closely to Whittle’s remarks. They go well beyond financial success. The other candidates (if they have the intestinal fortitude to follow Whittle’s advice) might also learn something useful.