I initially answered in response to your original claims that the sellers can't be making their $ back or that a sale of PVB, CCV or VGF would likely be driven by financial distress.
In my case (after using my PVB points to book 86 nights, at PVB standard or lake view/BLT lake view/AUL ocean view), I would still walk away with a cash profit plus the value of the 86 nights if I chose to sell. As you point out, most direct buyers probably didn't buy in with a plan to sell this quickly, but they may also see that they will realize a decent return on investment and decide to cash out. Some people find that membership isn't what they thought it would be. Others change jobs and maybe that impacts their ability to travel. Families grow (marriage, birth, adoption) and shrink (divorce, death), which also influences travel habits. Others may want to get into the Riviera as their home resort, which wouldn't have been known when they first bought in to Poly, CCV or VGF.
I'm not arguing your point, just letting you know why I responded as I did