I don’t think most people ARE sure he will lose. I think the majority of left-leaning people in the US (and beyond) are completely traumatised by 2016, and daren’t get their hopes up.
But the polls are indicating a Biden win, and the polls have moved on a great deal since since 2016.
Of course there is a lot of support for Trump. Nobody’s saying Trump has no support. But the polls don’t indicate that he has enough support to win.
Clearly enough Americans are OK with the job Trump has done over the past four years, for him to still be in the running.
I find that mind-boggling, but it doesn’t really matter what I think.
But Biden, also, has a huge amount of support. It’s difficult to see what’s not happening in your own bubble.
Also, Trump will lie, cheat and steal to win, so of course there’s a distinct possibility that he will be president for the next 4 years.
And meanwhile, the US loses its standing in the world - though vast swathes of Americans don’t seem to care, because they love Trump more than anything. More than their country, their freedom and their democracy.
Go figure. 