You are technically correct.....
DVC is a 50 year (Right To Use) RTU, but some resorts got less than 50 years such as BCV that has 40 years RTU.
Thus, 15 of the 40 years have been used and there is only 25 years left left (37.5% used and 62.5% remaining).
No matter, I am not too confident that prices will dramatically rise much more than the present value and, for sure, sometime in the next 15-20 years they will drop like a rock, and in 25 years it will be worth $0.
Imaging someone selling you a stock or bond that will be guarantee worth $0 in 25 years, unless the dividend is huge, do you really think that will dramatically increase in value?