Florida at least has some decent explanations, but North Carolina seems a little trickier. Democrats seemed to have the potential to make more progress there - they did win a lot more voters at one point, but it seems over the Obama years they lost them, or at least Clinton did, and perhaps another Democrat can make it up.
A steady stream of aging Boomer retirees, a slow-to-change Cuban population and a higher Democratic share of white support (which gave Democrats more room to fall, for numerous reasons, including their rural collapse) explains Florida.
In North Carolina, people who recently moved to NC actually voted more like NC natives than people who moved there a while ago, which suggests that the same retiree factor with Florida may also be happening there.
Poll
