Are you fucking kidding? Because Biden 2020 was a progressive platform and Harris 2024 was a centrist one. They weren't even remotely similar. Biden may be a centrist, but he's very pro-labor, and he could see how important the progressive base was that election, so he literally sat down with Sanders and hammered out a platform that they could get behind. And while I've got a lot of problems with Joe Biden, he actually was very committed to that platform. He really wanted BBB to get through and he kept trying to find ways to abolish student debt.

Harris, on the other hand, had a handful of disparate, vaguely left policy positions, like the first-time homebuyer's credit and legalizing pot, but her campaign was mainly centered on economic opportunity for the middle class. She also committed wholeheartedly to the most right-wing polices of the Biden administration, like arming Israel and cracking down on the border. But worst of all, she made bipartisanship and Republican consensus a huge part of her campaign, promising to add Republicans to her cabinet , campaigning with Liz Cheney, and even praising Dick Fucking Cheney.

TL;DR, Biden campaigned like Obama in 2008, Harris Campaigned like Hillary in 2016. And the results were the same.