Barring a Todd Akin-level gaffe from Biden, I think he is. He no longer has the luxury of running against a historically unpopular opponent, and now has a really poor record to defend. Biden is also hitting 50 in almost all of the key states. A lot more people are voting early or by mail, so the chances of a late event drastically changing the race are lower than they were in 2016.
My assessment, but I would add that Trump is in a position in which he has to do something incredibly reckless and get away with it to win. Such is possible, but he has had plenty of opportunity to do so and he has failed. If he were a normal politician (let us say John Kerry or Mitt Romney he would avoid something reckless and be satisfied with looking good while losing.
With the horrid behavior of Trump, if Trump were the Democrat and said much that I liked and Mitt Romney were the opponent I would vote for Romney. I do not want erratic leadership as pervasively corrupt, incompetent, and cruel.
It may be ironic, but Joe Biden wins in part on what Republicans used to win on. Biden is a man of devout faith; he has a conservative lifestyle, and he respects the veterans and active-duty members of the Armed Services, In 2008 and 2012 both Presidential candidates fit that pattern. But this is a matter of basic decency, and one that we need consider in every election. Without that decency (OK, a person can have weak religious faith or even be an outright atheist and have a strong moral compass, but one can still show that and it would be adequate).