I mean, early polls had Stabenow ahead by much more than polls closer to the election. She still won by 6.5%, but polls had her ahead by much more than 11%. I certainly don't think Trump is done for in Michigan, and Democrats would be wise to take Michigan seriously as a swing state.
Were voters' opinions of Stabenow as hardened as of Trump? Hardly. Trump isn’t done for in MI, but it’s kind of silly to assume that he’ll easily close an 11-point gap by talking about Biden's voting record when he barely beat Hillary Clinton of all people in 2016. I don’t even think that he or any other Democratic nominee will come close to winning MI by double digits, but they don’t need to win the state by a large margin in order to win the presidency. Trump’s the one facing an uphill battle here (and in PA/AZ/etc.), not Democrats.
No, but I don’t think their opinions of Biden are as hardened, either. Trump should definitely be worried about his current MI numbers (as well as his numbers in PA and WI), but especially if Biden’s strategy is to just talk about Trump, I could see a lot of the undecided voters breaking for Trump.