It's complicated. Since about 2000 all elections are tight. I think Bush Sr. could more or less not lost in 1988, the prevailing winds against the welfare state were too strong. Not anymore. The Dems are the majority but forces are keeping it around 50-50. So the possibility of loss is just there.
But there's something else. A presidential candidate in our time by definition has been vetted by a punishing series of debates, op-ed pieces, local interviews, campaign stops, primaries, conventions etc. It doesn't really matter what Whitmer or Newsom poll because they ain't done none of that.
There's something almost impressive about the modern American homeostasis. Coalitions, policies, politics are all moving at rapid speeds at the moment, the ground constantly shifting. And yet federal control remains a competitive knife-edge. It's hard to say which is tail and which is dog.