People lost faith in the neoliberal status quo in 2008 with the financial crash. Instead of bringing meaningful change to that system, Obama propped it back up – nothing changed. Come election time, people didn’t want more of the same, which is what Clinton and Harris offered. Biden is a fluke in this, but honestly the pandemic played a big part in his election. The only one offering change was Trump. That change was fascism but it was still a change.
Also, Obama constantly went for bipartisanship with Republicans who were actively pushing for an erosion of our rights. When the opposition is as actively hostile as Republicans, cooperation is complicity. Obama was the PRESIDENT with a democratic majority house and senate. He should’ve made the Republicans bend to HIM, not the other way around. The fact that Republicans gained power at all in the 2010 midterm after the clusterfuck of the Bush admin shows you how weak and ineffective Obama was.