That depends on your definition of classic and vintage. Personally, my definition of vintage is purely based on age (25+ years). In that case, a POS from 25 years ago can be a POS today and won't be classic. On the other hand, a POS 25 years ago can be a classic today.

I don't know enough about bikes to give an example but I can use cars. An AMC Pacer was a POS, now, because the the kitsch value, it is a classic. My first car though, a Chevy Chevette, was and always will be a POS, and will NEVER reach a classic level.

And just to clarify things, my definition of classic is based on aesthetics and not on age.

And, pardon my French.