As always, theres a lot of uncertainty and a lot can happen. But it took a wild series of events, including an FBI chief going rogue to relaunch a negative Clinton story two weeks before the election, which polling showed hurt her right at the end.
Biden has a bigger lead than Clinton ever did, and Trump has a lot working against him: the economy is in a recession, and even the rosiest scenarios still have us with recession-level unemployment at the end of the year. He screwed up the coronavirus response, which isnt going anywhere. Hes on the wrong side of nationwide protests. His approval ratings have been the most consistently lowest of any modern president, and his one bright spot, the Obama economy he inherited, is gone. Hes made no efforts to expand his appeal beyond his base, which currently makes up 40% of the electorate at most, and he cant win with that. Polling has him behind in most swing states, and hes doing especially bad in Florida. Hes lost his advantage with senior vote, and is underwater with every single group aside from white men, and his margin with that demographic isnt enough to get him to 50%.
On top of all of that, even states were thought safe for him, likely never were. Despite his big margins in Iowa and Ohio, his actual vote percentage in these states was just 51%.
Altogether, 2016 was a weird election where Trump got very lucky, and 2020 is simply looking like a year that wont go his way. Being an incumbent is a huge advantage during good times, but these ARENT good times, and voters typically blame the party in the White House for that.
Unless something big happens that significantly changes the state of the race, Trump is almost certainly going to lose. Without that, hell need to hope coronavirus and existing GOP voter suppression tactics suppress enough Biden voters, combined with a polling error that breaks his way, will be enough to put him over the top.
Polling errors tend to only shift things a few points though, voter suppression can only do so much as record Democratic turnout in Georgia has shown, and when Wisconsin voters were forced to vote during a pandemic, they STILL showed up in high enough numbers to put the Democratic Supreme Court nominee there over the top. So overall, I have my doubts Trump can rely on any of this.