Right vs left wing is a silly idea. What does my position on health care have to do with my position on defense? Now consider the above question, but substitution any two of the thousands of different things the government does. At best the two are a loose alignment, but there is no unity.

Support for Trump is not crumbling. His base still supports him. What is crumbling is the alliance of "right wing" people who never really liked/supported Trump, but were willing to accept him for the alliance. This is enough to turn the next election, but the "right wing" (again, whatever that is...) is still there and mostly hasn't change positions.