I posted about this yesterday, but essentially by not making it a key issue in 2020 he basically defaulted the issue's advantage to Trump.
One of the biggest mistakes Biden made in 2020 was not running on the economy. He ceded the entire lane to Trump, and while he won that election you are starting to see it hurt him now. Obama ran and won on the economy in 2008, so while it wasn't doing too hot in 2012 he was able to hold onto his talking points and hold off Romney quite a bit on it. Biden never even tried to make the economy part of his 2020 message so by default voters are going to prefer Trump on it. The economy doing poorly right now doesn't help him either, but he gave up his chance to win on the issue four years ago.
He didn’t explicitly run on the economy in 2020, but it was a part of his message. Biden ran on the theme of “returning to normal”, which included solving the Covid issue and its effect on the economy. I think his message this year should thread the needle mentioned by ModernBourbon.
Something akin to “Things may not be perfect right now, but we’re moving in the right direction. America under Donald Trump was a mess of chaos and tax payoffs for the rich. When Obama-Biden gave him the keys, the American car was gassed up and driving smooth. He didn’t change the oil, never put air in the tires, and drove all the gas out of the car,
then turned around and got us stuck in the mud with the Covid pandemic. I’m still digging us out of the pandemic mud that Trump let us drive into. We can’t give him back the keys to the car now!”
