You don't have a theory. You have a question that will eventually be worked into a specialized statement that you can test. That would become your hypothesis. I would suggest taking a random sampling from more than just this site if you hope to substantiate your leanings (bias). For the record, there are about fifty or so drummers and musicians I work with through my church. All but a few play vintage gear and most all are still in school.Most every studio I've recorded inhad multiple vintage kits and a huge variety of vintage snares. I assure you, there was no age limitations put on the drummers. I'm your average two thousand year old man.
Actually I do have a theory, which in the philosophical sense is a proposed explanation of a non-empirical phenomena. The subject matter of such a theory may consist of ideas as opposed to empirical data.
As such my idea (theory) is that; a) a majority of vintage drum players/collectors are of a certain age (approxamately 50-60 yrs. old)
b) as a result of our age, we put more value on drums of a certain era, c) which then impacts the demand, collectability and value of those drums.
Clearly, I am not speaking scientifically as I have no impirical data, merely anecdotal observation.
I've posted my theory here for comment and discussion not in an effort to prove or disprove, but for academic discourse, not unsimilar to the approach of the philosophers.
Just curious as to how old you really are, 2000 yr old man? In your post above you said "in school" what do you mean by that.
I am still 50 myself, and hope to remain for many years to come, although I will be celebrating my 1st anniversary of my semicentennial birthdate shortly.