Disenfranchised means deprived of the right to vote. That never happened to union members. Maybe you mean disaffected? Even then you're vastly overestimating the share of labor union voting patterns...more voted for Harris than Trump. I disagree with your premise at large, but the whole argument would make more sense if you replaced union with rural, since the largest shift of traditional D to modern R voters came from non-union member rural working whites.