Sorry to hear all these accounts of peoples' cycling coming to an end. It's somewhat hearting to hear that some of you don't miss it, and I know we all get something different from riding.. however personally I've come to the conclusion that when I can no longer ride my life will effectively be over.
True, in the 20yrs since I bought my first road bike at uni my riding has waxed and wained; usually faltering when living back at home and not liking the riding around here. I think in the beginning my mental health was generally better, plus I don't think I consciously recognised the benefits of riding so much. Years later I struggle to imagine much quality of life without getting out on the bike, and am fully committed to a future where every journey I can is undertaken on two wheels, for all the usual reasons.
As I've aged my attitude towards what I want from the bike has changed a little and now I'm rarely if ever concerned by speed - instead just getting out or going shopping, knowing that doing it on the bike will make me mentally and physically fitter, save me money and ever-so-slightly reduce my burden on the planet.
It's interesting to look at this from a gear perspective too - in other interests I've often worked my way up to some quite nice kit, and have certainly coveted it in the past. While it would be untrue to say that I've not got excited about a new bike or piece of equipment (the pinnacle probably being my Croix de Fer in 2020); for me the pleasure remains largely rooted in the ride itself rather than what I'm riding. As it happens I've not used the CdF for months; instead using my Fuji which is considerably less lofty and arguably inferior in many ways.. while I get nearly as much pleasure getting out on my battered old budget Raleigh.
I've certainly had other interests where I've swung from totally, obsessively immersed to barely interested; however while not without benefit I've not found these to be as profoundly good for me as cycling has proven.
Stay active if you can folks, even if it's not two wheels