Frankly, David doesn't have enough points, and is going to have to raise the amount he pays members ($11 a point) to sweeten the pot and get more points to keep his customers happy. That means that to cover his costs and turn a profit, I'd expect David's points to go up by a buck or two in the next year. When you rent points from David at $14, and I can rent my points to David for $11, I'm not going through the bother of doing my own legwork for less than $12 - and probably $13. But you won't buy from me if you can get the points from David for $14 - but you can't for BLT and VGF - he doesn't have enough points with advantage at those resorts. So you are stuck with people who are able to charge more because they can compete with David and make more than $12 or $13. Plus, owners at those two resorts paid a LOT for their points - their points simply have a higher fixed cost than my twelve year old BWV points - which I could rent for dues at this point and not feel "out" money (but why would I when with a couple of emails, and a few clicks on the computer, David will give me $11 a point for them).
Now, you can find points for less than $11 or $14 - but they may not get you a walk into Epcot or a room on the monorail. The seven month window can be a gamble for those resorts. And if you have an owner who is a planner - why would an Epcot resort owner not plan on renting during F&W when their points WILL move fast at a premium. And the monorail resort owners don't even need to worry about timing.