I'm not sure it'll ever get big as muscle car status but they'll always be collectors for anything. Not so sure about modern mainstream bikes from the big companies being how massed produced things are but the small builders will always bring loyal fans. But will my son/daughter see anything of interest in my bikes or just see them as bikes. My kids raced BMX and each have a few bikes of their own and with me having bikes, books, movies, etc... dealing with bikes it may keep a general interest and know they're more then just "bikes". I hope at least with the two frames I built they'll keep them in the family seeing their names on that downtube will be something special to them.
I mean it could be the same as me like ten years ago. I had no interest in road bikes but always had nicer bikes and raced in some form or another. A change in riding and interest got me into vintage road bikes and the same could go for anyone else. Something you might see or remember from a certain time may trip that trigger and spark up interests into vintage bikes. Much like I used to be heavy in Hip Hop music in my high school days but upon listening deeper I enjoyed the samples they used and looked further into it and discovered the musicians they sampled music from and got into older soul and R&B because of that.
Same goes for the many stories in this forum you hear about of a friends relative who's got an old bike in their basement/garage. They give it to someone else and hand a story about the bike and it strikes a chord with the lucky recipient and they get stung by the vintage bee and it's all downhill from there. Lol!