Like a couple years ago the rumor was resales could only stay at their home resort.
That was a timeshare salesman. You know the joke:
Q: How can you tell when a timeshare salesman is lying?
A: His lips are moving.
The "home resort only" thing is a bald-faced lie to try to get someone who is saying no to a developer purchase to say yes. This is a completely different beast.
I do expect that someday the AP discount will become less attractive or go away entirely. Based on the way Disney's accounting works, I'm fairly sure that DVD has to "pay" the Parks division something for this discount---probably not the full value, but probably something. That has to come from DVD, not DVCMC, because it's not an operating expense but is a sales incentive. But, over time, the Membership size (and number and value of the AP discounts) grows, while the monthly revenue from sales stays relatively constant. That's not sustainable in the long term.
That's all a guess mind you; I don't have any inside information at all. But, if you follow the money, that's where it takes you. The only real question is whether or not there is a transfer from DVD to Parks. It's possible that there isn't any such transfer, and Parks is doing this on their own because it increases ticket revenue from
DVC Members overall---in that case, there is no sustainability problem, and the discount can continue as long as Parks thinks it brings in more business.
DVD/DVCMC probably doesn't care if existing members sell their contracts---someone else will buy them, so the Dues still get paid and that someone else will still stay in the resorts. Resale prices will drop a bit because there is more supply. There might also be a bit of a reduction in demand---some people buy small resale contracts only because of the AP discounts.
The only thing that will make DVD take notice is if direct sales are impacted. I'll wager that we are at a point where a reduction in resale price probably won't make a difference, because the gap is already so large that anyone who is considering resale carefully nearly inevitably goes that route. The absence of an AP discount might very marginally impact direct sales marketing, but probably not in a material way. Most direct purchases are coming from those looking to bottle the magical feeling they have on that trip and keep it for years "at today's prices." The AP discount is a sweetener, but that's all. A good Guide can work without it.