I know where most of my old bikes have gone. My Spyder Bike went to an underprivileged kid when I got Big Red. I sold my Triumph 10-speed to a co-worker, in Ohio (and he crashed into a tree and broke the frame).
I have sold, traded and given away many other bikes. I may not know who, particularly, owns them, but I know that they went somewhere.
Yet, there is one bike I can not account for. The purple Western Auto Buzz Bike that I got when I was 14 is missing in action. It is no longer at my parents' home, but I have no idea where it went. It was the last bike I got before I got my driver's license, and I lost interest in when I started driving. I just recently realized that I can't account for it.
Big Red is still around. I have had it since 1971, so it's not like every bike I had before I started driving is gone. I just don't know where that purple bike went.