I’m not arguing Biden can win, obviously he can as well as Trump. I ask where you are getting the data on Democrat’s moving into Republican areas. By what percentages are they moving? And where are the Republicans going? Are they becoming dems?
Also if Trump wins Ohio by a small margin he still wins all the electoral votes, so has does that help Biden? Trump lost the popular election last time.
Two answers on states (and people) going from Republican to Democrat:
1. People tend to be leaving California, Illinois, New York for Arizona, Texas, North Carolina. Trump would argue because of failed policies in those Democrat states, and, even some Democrats like myself would say he has a point. Those individuals bring their politics along with their clothes and furniture.
2. Suburbanites, especially women and especially people who are more affluent, are morphing from Republicans into Democrats in suburbs throughout the nation. Lots of reasons for that.
Conversely, there are no segments that are going hugely from Democrat to Republican, although some entrepreneurial Latino and Black men maybe are going in that direction.
On Ohio, if Trump barely squeaks through, it means he will lose big in some other states. Ohio should be a cakewalk for him.