It's fascinating to me that so many Blue Avatars here are convinced Trump will hang on to the Rust Belt.
2000 was the last time the Democrat garnered fewer raw votes than Trump 2016 in MI and WI (2004 for PA), so why in the world would he be assured to keep them while losing the White House?
Because of overall trends. The rust belt states are trending republican at a fast rate as the sun belt trends toward democrats. The reason for this is republicans becoming more populist and in some ways economically liberal.