Curious as to where you got these stats. I'd say that I'd notice the same thing about riders that quit, but if you have a source for this information it would be really interesting to know more about it.
I did not quote/use statistics (if that's what you mean by stats) and do not have any actual data to back up anything I said.
But .......
I have seen, known, mentored, ridden with, hungout with, palled around with, listened to literally hundreds if not thousands of riders since took up riding at the age of 15 in 1967. And therefore am a self proclaimed know it all when it comes to this sort of thing....like most cranky old riders.
Based on what I have observed, I stand firmly behind my conclusions.
It's just the way it is with riding, you either love it enough to continue doing it regardless of the risks involved, or you stop, because of the things I mentioned in the original reply.
That pretty much happens within a few years of that initial introduction to the sport. If anything, 5 years is being generous, I would venture to guess that most of those quit riding people are gone in under two years.
Do I have a poll or study conducted under strict guidance, and cross checked, no. I just know, that's all. I am also a good guesser!
As an example, browse motorcycle for sale ads on a regular basis and you will agree with me soon enough.
If you do a search on CL using the term "wife", or "selling due to..", or similar , you turn up many results like this one:
http://sfbay.craigslist.org/sby/mcy/923749972.html
I couldn't tell you the volume of listings I have seen like that.
Another thing, I am 86.42% sure of, is that all official stats are made up on the spot as a convenience.
Additionally I am 100% sure that I am a walking encyclopedia of riding lore and information, with a measure of bs thown iin as well.