Depends on what kind of ATC you are doing I think.
Some of the guys admit to not wanting to work by the 'seat of their pants' as they get well in to their 50's even though they can still do it well. Add to that the 'environment', those who can afford financially to 'step back' usually do.
In a more sedate workplace, things may be different - but some places still require a fast 'CPU' - and everyone's CPU slows down as you get older, no matter how good you think you are in your 30's and 40's.
Luckily I can afford to leave now - and I consider it more and more every day I see another 'smartest guy in the room' come out with a 'new' idea to make the place work 'more efficiently'!
That is probably the reason more guys jump - not the job, but the 'environment'.