actual point: if I'm the best at what I do, and nobody is pushing to become better than me, I will stagnate because nobody else has exposed a better possible pinnacle.

Iron sharpens iron.

This doesn't preclude that though. Maybe it's because I'm a weightlifter and while we compete with one another we really don't, but my own numbers can be my rival. In fact, they're a much more effective rival than anyone else at the gym because they can never be permanently beaten, they can never retire, they will always demand more. If I wake up tomorrow and through some miracle I'm the best weightlifter on earth and can bench a 1000 pounds, 1005 pounds exists whether someone else can lift that much or not. If you're Tom Brady you don't need Peyton Manning in order to throw more touchdowns and fewer interceptions, you need to throw more touchdowns and fewer interceptions. If your rival has a career-ending injury does that define your pinnacle? Not if you're actually in competition with yourself it doesn't.

the greatest i know of are interesting characters because they can invent rivals and adversity where none exists. this comes across oddly and makes for great stories about their mania for competition