What about the other 83%. How do they manage? I agree that superfluous use of ICE vehicles should be strongly discouraged, but people still a viable alternative appropriate for all ages and physical fitness.

Cycling rates actually increase as people get older in Netherlands: https://www.researchgate.net/figure/Bicycling-share-of-trips...

Another thing that quickly disproves this idea that cycling is only for young people...

It has little to do with age - and more to do with viability.

If you live an American lifestyle, and you live 5+ miles from a grocery store - cycling is not a great option.

If you live in a city like Chicago or New York or... Amsterdam - there's really no reason it can't be viable - except in the US case a lot of places that could be cycling utopias are severely lacking infrastructure.

In Netherlands, commute rates drop to their lowest for people in late 20s and early 30s because this is usually when they have jobs / living situations that require commutes too far for a bike - though how much of this is due to choice vs lack of adequate housing in cities (global problem) is unclear.

60s are not "old" in Netherlands. At 60, people aren't old and frail - they're not much different from people in mid to late 40s.

The average person doesn't start to get frail until late 70s - and at this point - you probably shouldn't be driving either...