Trump Support: Who’s Left?

Since Trump’s attacking the U.S. military has cost him the support of a great swath of the right wing, one wonders: who’s left?  With the left and center gone, the only remaining constituencies appear to be a) hardcore racists/gun nuts, and b) people whose news source has them so completely terrified and so badly misinformed that they’re missing all current events.  Given the highest-rated Fox News shows have no more than 7 million viewers, and there are 18.2 million veterans alone, how can this possibly work out?