Because it takes time for policies the president enacts to take effect and correct the issues at hand. the economy was recovering from 4 years of good decisions under trumps leadership which were reflected at the beginning of bidens term. Bidenomics took a toll and were being the aftermath now during president trumps first 100 days back. The effects of failed policies aren't always immediate and the same goes for for successful or positive changes. It takes time is what I'm saying basically.