My take on the time value of money is that the equation has to include the annuity for using the principal to pay for cash accommodations. And that, by the time you add in an inflation constant to thy, y are coming kind of close to making stuff up, and having so many numbers running around the equation with so many plugs, it more of an exercise for us math geeks. Moreover, for our family, where the true cost has been is not in owning- buying and paying maintenance fees- but in using. Park tickets, food and airfare have all increased in cost faster than expected, but for our family Disney was never the given. The simplistic version probably works fine for most people, because they don't have the discipline to invest the principal.
And that in the end, this is something that allows you to enjoy vacations. You can afford it, or not. You'll never save more money with DVC than you would making a dozen other choices, including staying away from expensive WDW, staying in values, cheaper timeshares. If you can afford it, it'd like owning a nice car. Your Mazda Protege will get you where you are going, but the BMW is more fun to drive.
And that in the end, this is something that allows you to enjoy vacations. You can afford it, or not. You'll never save more money with DVC than you would making a dozen other choices, including staying away from expensive WDW, staying in values, cheaper timeshares. If you can afford it, it'd like owning a nice car. Your Mazda Protege will get you where you are going, but the BMW is more fun to drive.