People have just gone "all in" on Trump. Part of it can probably be explained with "sunk cost" but I think it's mainly a symptom of people struggling with the confusion and hardship of the modern political/economic landscape. It's not even unique to the right, tbh. "Blue no matter who" is the same phenomenon, as are people going all-in on idpol or even anarchism or communism. Before anyone gets mad about those last ones, just think of all the ardent reds who know basically nothing about theory (I'm not totally innocent of that characterization myself).