I put it into this aspect....SOUND! I don't believe that it will die, or go a different route, and believe that a 50's, 60's kit will always remain in demand to the next generations. Same way a Les Paul, and a Fender Telecaster or a Stratocaster is in demand. For the sound!
Needed to mention as well, that regardless of the collecting aspect...I wanted it as a kid, but could never afford it...now I have the funds, so I am going to own it! Problem is, I only wanted one kit or a snare back then, so I guess with age, comes hoarding!
Nevin