Not trolling. Most starting nfl qbs are capable of greatness with the right team around them. Look at Russel Wilson as an example. MVP seasons on a great team, utter garbage on a bad one. It will happen to Mahomes at some point, and when it does I want you to think of me.
Yes, players regress as they get older. Sometimes it’s gradual and sometimes it’s a cliff. There’s tons of examples of elite players who wake up one day and just don’t have it anymore. So yeah, Mahomes will one day become average, and then subpar, and then no longer able to compete at an NFL level. But right now he’s arguably the best quarterback of this generation.