As has been the case for decades with the Democrats, if people had come out to vote, then Kamala would likely have won. But the turnout was down. Historically, that always favors the Republicans.
What were the people staying at home thinking? What we've heard is they were thinking something along the lines of both parties are the same, so it makes no difference, or they were grousing over how the Democrats weren't forthright about having a primary. Well, they're now realizing both parties are not the same, and those grousing about the lack of a primary are now feeling foolish for sitting out.
BUT - what I'm starting to get really sick of is liberals blaming our current woes on the Democrats. I'm sorry. You knew what Trump was and you knew what was at stake. If that wasn't enough to motivate you to get off your rear end and get to the polls, then that's on you.