Personally I don't think Spanking will ever become mainstream because it is just not PC to hit another human.
I think there are far more people out there that have a interest in spanking from both a sexual & a discipline point of view but will not openly talk about because of fear that others will class them as perverts or violent thugs.
Being able to go to a therapist would be so beneficial for lots of people who can not talk to any one else about certain issues and needing to be spanked afterwards. We all know how de-stressing it can be to be spanked & also to spank.
It would be great for these people to be able to find a person will will Listen, Mentor & Spank during appointments, of course there are lots of people who say they would do this for you but have a dark ulterior motive.
I am sure of one thing though that this could be made a reality if people want it