I think there are more Trump democrats this time. Was there much of a #walkaway movement back then? Or Blexit?
I would say there are two factors.
1 - In 2016 there were a lot of Bernie Bros who voted Trump to get back at the Hillary camp. Will they stick this time?
2 - Promoted by the Trump campaign, so grain of salt, there could be a large Democrat contingent coming over. But we have Never-Trumpers, does it even out?