I suspect this is exactly the way the Democratic Party wanted to win...by the narrowest possible margin, so that they cold reclaim power and the fundraising possibilities that come with it, while being excused from owing the base much of anything.
Also, it is worth noting that, despite all the celebrity Republican endorsements, the Biden-Harris ticket received virtually no additional Republican votes than the Clinton-Kaine ticket received in 2016- which raises the question, did the obsession with getting Republican endorsements achieve anything at all?