I am not sure that Independent decline has been a result of Trump hate which drove some independents into the Democratic party to fight Trump. Perhaps the same happened to fight the Democrats as well.
On reflection I may be right or I may not be but its probable, I think. It kinda folks taking sides. The problem, I suspect, is defining the sides as, I think, anything one side says about the other just stirs the pot and nothing really changes.
I base this on absolutely nothing and suspect your probably have more fact than I and admit that I may be completely wrong. It does seem, now, that the number of independents is growing, however.