There is a big reason for the new re-sale restrictions put in place at Riviera and likely all future resorts: They are counting on these restrictions to drive people to Direct over resale, without the need to rely on perks.
So I certainly wouldn't rely on significant AP discounts still being available in 10 years or further.
Before you know it, we will get to a point where a direct buyer has access to 15-20 resorts, while a re-sale buyer has access to only 1 resort (if a Riviera or later resort), or a limited portion of older available
DVC properties. (By 2042, wouldn't be surprising if a resale buyer is limited to about 10 out of 20 possible DVC resorts).
Over time, I expect reduction in directperks that actually cost Disney anything significant, when they will rely on the resale restrictions instead.