Because ultimately, it's a fun kids game, and (I testify first hand) you don't stop enjoying fun kids stuff just because you get old. And I say again, he could, barring serious injury, play effectively as long or longer than Brady did. True about not working to Social Security age (although I have a job about 3-4 hours a week even at age 75), but IMO, playing football is more fun than work. Who among us wouldn't if we could?
runpMc, I sure didn't see what you saw - a guy not having fun. Maybe due to injury or uncharacteristic lack of success at times, but in general no. And he went out of his way to demonstrate that his legs ARE still plenty good, at least for his age. And saying NOT in all caps/being so definite about indefinite things, I told my oldest grandson when he was 12, about 15 years ago now, always say "it seems" or "probably" or "IMO" because if you say something like you know for sure and you're wrong, you're basically lying.
And "major cap gymnastics" are like shit - they HAPPEN regularly, not to mention the hugely increasing cap.