Well, since the average annual cost of owning and operating an automobile in the US is about $8k, the folks who are riding their bikes instead of driving have probably been better able to save for their retirements.

Also, the expensive part of retirement is the later years when one can no longer perform basic functions. I'm told that the number one reason people have to move to assisted living is because they can no longer get onto or off of a toilet. I suspect that folks who have been long-time cyclists are less likely to lose the ability to perform such "squats" early on in their retirement years.