I'm not at all trying to defend Disney here, just trying to make sense of their reasoning. Please feel free to poke as many holes in this thought process as possible. I just can't imagine they want to go from being one of the top timeshare companies out there to one that wants a large portion of their customers to either be saddled with debt or enter foreclosure because the resale value of their contracts moves to essentially nothing right after they buy in. That's possible, but it's quite the about face not just for DVC, but for Disney as a corporation.
This could potentially be a defensive move by Disney, not an aggressive one. They are opening up two new resorts in the coming years, and have to justify selling at higher and higher prices. At the same time, the existing contracts are moving closer to their expiration dates, and eventually prices will start dipping. It is possible that they fear people will be comparing $250 a point at the Reflections resort to $75 per point for BRV resale contracts 7 years from now. Considering that most people own DVC for only 10 years or so, buying close to expiring points and then using them at new resorts would actually be a good plan under today's system. By restricting those resale buyers, Disney can make it easier to justify their high buy-in cost to get into the newest resorts.