Undoing the amount of damage they caused takes time. Biden inherited a spiraling economy, hundreds of thousands of people sick and dying, and a coup attempt that nearly got a bunch of people killed.
Not to mention all the idiotic shit the prior president had done while in office, such as austerity cuts that fucked social programs, legal systems, and low and middle income Americans.
It will take 12-16 years of unified democrat rule to fix corruption, regulatory capture, anti-trust for monopolies, universal healthcare, infrastructure investments that don’t get slashed by idiotic presidents, etc.
Four years of chemotherapy isn’t nearly enough when we have policy tumors and R&D funding cut abscesses from fucking idiots like Regan, Bush, and Trump.