I fully agree with your conclusions, but have different thoughts on some of the finer points. I am not so sure the pool of renters is much greater than the pool of owners - in any market, supply and demand typically meet at the market price; if your assumption was true, the price per point would go up until the two pools would be of similar size. And in general, in the long term the renters have more options - book cash reservations with Disney, go elsewhere or simply stay home; the owners, on the other hand, are stuck in long-term contracts and they would need to either go to the
DVC resorts themselves, or rent the points out.
A business like David's would not go under because of losses - it would just fold when it runs out of cash. Right now it is probably fueled by the 30% deposits retained from reservations through February 2021, so assuming only half the renters would do credit card chargebacks, it may last about 5-6 months.