It is weird how some of these bikes get abandoned by the PO.
There are many reasons, the obvious is most people are passionate it about bikes like we are.
Another reason is they do not see the bike as a valuable asset, and just let em sit outside in the weather.
15 years ago, that bike could have easily been purchased for 50 bucks or so, worth next to nothing to the owner and he may not know the value.
My biggest fear in life is when I die, my wife sells my bikes for what she thinks they are worth! [$200-300]