Correct, DVC points can only be banked once and then you lose them if you don't use them. So DVC owners can really only put off a trip for a year before they have to either use their points themselves or rent them out to someone else who will almost certainly give Disney money for park tickets, food, and merchandise. And if you sell your contract then you're either selling to another person will will either give Disney money for those things or rent the points to people who will - or Disney buys the contract from you via its right of first refusal and then resells it to someone else, thus making additional money off of your contract PLUS the tickets, food, and merch money from the next buyer. What you can do as a DVC owner, though, is use your points to stay at a DVC resort and then buy food off property and not visit the parks and just enjoy the pool and any other amenities that don't cost any additional money.
However, where Disney could shoot itself in the foot is that creating bad word of mouth regarding DVC could limit the market for future DVC resorts and the existing DVC resorts in its portfolio. They still have unsold points for Riviera - which has some absurd restrictions on its resale contracts - and "new" DVC rooms at Grand Floridian and a new DVC tower being built in Anaheim. I'm sure they know there is enough demand for the Grand Floridian rooms or else they wouldn't be converting them, but if the Disneyland DVC tower has the same restrictions as Riviera AND they continue to not offer new APs/Keys for DL then that's going to hurt demand for that resort's contracts.