To be fair, 60 is a lot more than 40. There are many top athletes in other sports at 40 but very few at 60.
It's my first time playing a proper FPS, yay Steam and Linux compatability.
I would not be surprised if the 20-something pros in stuff like FPS games would still be quite good at them when they hit 60-- provided of course, that 1) life doesn't get in the way, 2) that they still playing the games regularly, and 3) that the genre even still exists at that point.
---
I know one older gentleman playing a FPS. He is not very good, but better than the majority.
It's all about community though. If you play on the same server or a not-very-popular game, you would soon know all the "regulars". The actual game is there just to hook you in. You stay for the community.
I don't think the pros would be very good. If anything, I'm worried about how much carpal tunnel syndrome and other health risks they put themselves through by being pro.