DVC is in theory an economic way to visit WDW, but WDW is still expensive. Also, for many of us we are buying DVC because an "ordinary hotel room" simply won't do - we want the suite, the kitchen, the 2 bathrooms, the privacy of a bedroom door from the kids, whatever it might be... DVC should not be bought with the idea of "saving money"... it is more economical than other ways to visit WDW annually, but visiting WDW annually is hardly a value proposition.
I could see us at some point growing our membership to around 500 points, I could also equally likely see us shedding our points down to the minimum for direct benefits and/or eliminating our interest in DVC entirely. It is a lot of fun to go to WDW, but it is incredibly expensive. Also, we have recently been getting very interested in
DCL (another expensive vacation), and could see us saying we are only doing day trips or overnights at S/D instead moving forward.