Iv noticed that lots of people who were previously Extremely famous really lost popularity points after losing to Ali(Foreman being the main exception due to his grill and comeback) Is there a reason for this?
Who are you thinking lost popularity after being beat by Ali? I don’t know much about the history of the era just seen all the fights.
A simple case of he beat the man who beat the man, that beat the man. It wasn't that he " killed" any fighters career. He simply did it the right way by beating them in the ring. While they mattered I might add. When Liston was seen as a indestructible force. Ali beat him, after losing in the greatest heavyweight fight in history to Frazier, Ali won the next two against him. When Foreman was seen as indestructible force # 2 and had destroyed two fighters that gave Ali hell in the ring ( Norton and Frazier) public perception actually feared for Ali's safety, yet Ali found away to beat Foreman, and actually ruined him for over a decade. Plus Ali fought a plethora of good to very good heavyweights along the way, he didn't just sit on the championship as many did. Ali didn't "kill" any fighters career. Ultimately he actually enhanced them, and made them more money than they'd ever make.
Nah, it's the opposite if anything. Would guys like Terrell, Norton or Shavers be as remembered today if it weren't for Ali ? Few would even know who guys like Henry Cooper, Doug Jones, Karl Mildenberger and Brian London were if they hadn't fought Ali.