Perhaps there is a mass of people who thought Trump would be tamed by the office, and the whole bureaucracy surrounding it, but clearly that has not been the case.
Everything fitted into place for him last time round, against a deeply unpopular rival candidate and he ran a very clever campaign.
He attracts very vociferous and manic support, but this is an occasion for the ordinary citizen to have their say. The sort of people that are otherwise busy paying their mortgages and rearing children to be going to rallies. Trump will retain a lot of his support, but he only needs to lose a small amount to turn individual states and I can't see very many people who didn't vote for him last time now doing so off the back of the last four years.
In that sense, I think Biden has hit the right theme calling this a battle for the soul of the nation, and whilst I think it will be closer than previously thought and a likely ugly aftermath, I still have faith that the majority of American voters in enough of the swing states will opt for Biden.