First of all, realistically, what is 'The Time Value of Money,' to most people? Zero. Because if people didn't take their money and put it on DVC points, they almost certainly WOULD NOT be investing it. Instead, they would be spending it on something else - a RV or motor home, a boat, an expensive trip to Europe, or whatever. We are talking here about the difference between Investment money, and Expendable money. The Expendable or discretionary money is what pays for DVC for most people, and it would not be for Investments. So, buying DVC and having some DVC points that DO have real value in the market place is perhaps one of the most cost effective things they could do.
It is true that there is no guarantee that DVC will keep going up. But it essentially HAS kept going up for 25 years, ON AN AVERAGE. At ANY point from about 5 years ago to 25 years ago, if I had bought DVC, I could sell it now for more than I spent on it. And that is at the Direct price. If you purchase at Resale, you could almost always get all your money back if you just wait 2 years or so to resell. (Vero Beach and HHI being possible exceptions, BUT, they are special cases.)
Recessions come and go. Yes, a recession WILL come. But then it will also go away again. If someone can hold their DVC points through the recession (and use them during the recession, or rent them out), then they could still get all of their money back, plus more, a year or two later.
The biggest fly in the ointment is whether people CAN depend on rental income. I'm not at all sure that Disney can retroactively deny all future rentals. In fact, I am pretty sure that they CANNOT. So, they might be able to put up some roadblocks, to make it a bit more difficult, but I think people will always find a way around that. And I think Disney knows that, so it probably isn't even a battle that they want to fight. After all, you can be darn sure that Disney is going to continue to raise their prices for their hotel rooms. And raise them, and raise them. As the cost of their hotel rooms goes up, DVC points also become worth more and more. And this rental market is a market that DISNEY is creating.
Lastly, don't confuse Disney with DVC. Disney essentially 'owns' DVC. Disney people RUN DVC. But DVC is a separate entity, and, though it might POSSIBLY cut into the profits of Disney's HOTEL DIVISION, when people rent out their points, it probably matters not a whit to DVC itself whether people rent out their points or not.
I do think it would be worthwhile if we could find some way to use the Owner Associations to put independent owners onto some of the boards at DVC. I don't know if this is possible, but it would be a good thing. And if we can't do that, then the next best thing is to try to find ways to make sure that the people who run DVC are running DVC, and not just working for Disney.