IMO, you are over-thinking this. Selling timeshare is much simpler than you seem to be describing. It is an aspirational purchase, and it is sold, not bought--and both of those make a big difference in how things work.
Most guests on the tour have no idea how
DVC works, or that the resale market exists. They are on vacation, having the time of their lives, and one of the Kiosk/Resort Reps (or maybe the in-room DVC TV loop) convinces them to take the tour. On that tour, the Guide explains to them that they can bottle this magical feeling of vacation and experience it for many years to come with some very affordable monthly payments.
Some of those guests buy. And, when they do they feel really good about it! After all, they just made a great investment in their family's future vacations. They
do not want to know that it was a bad deal, and so they do not go looking for reasons that it was. How many people find there way there to DIS during their rescind period asking if the purchase was a good idea? Not many. Even the few that do don't always rescind, because (a) they don't really want to and (b) enough people tell them that a retail purchase is a fine idea.
This isn't unique to DVC, where the resale contracts cost real money. A Wyndham contract is worth less than ten cents on the dollar the instant the ink on the contract dries. Yet Wyndham is very very good at selling timeshares.
Over on TUG, people used to say that the Internet would bring about the end of timeshare sales. It hasn't happened, becuase...
...of course they are not. But, they are
human, and do things that humans do---including make decisions based in large part about how they feel.