I think the results would be interesting. You could go back to 1991 and get and plot that data.
I would also look at the profit per point divided by the cost of the contract. I would then compare that number to 3 month t bill rate.
In 2003 bcv was 5.5/72= 7.6 percent versus short term rates at 1.0.
In 2005 bcv is 5.5/85= 6.4 percent versus a short term rate of 4.0. When short term cash goes to 5 % the spread will be even tighter.
In 2003 a buyer could justify buying a contract to rent. 7.6% v.s. 1.0%. That is no longer the case. I think some buyers add points because they have owned points and the price has gone up and if they wanted they could rent. I think some people buy contracts to rent. I would guess less than 5% buy to rent.
From a renting point of view, borrowing to buy and then rent will not make sense unless point values continue to go up. Personal villa use is by far the best use for points.
I don't rent and am borrowed out to the max. However when I bought bcv in 2003 I looked at those numbers to justify a financial "value" to the points. The purchase made sense based on renting. I had and have no intention of renting. However, I felt if needed there would be a buyer who buy just based on the rental income versus the short term treasury rate.
We stayed at wilderness previous to buying. We have stayed three times since buying. These points are strictly for personal use. I look at the rental market with curiosity and note the rental prices has not tracked the rack rate . I would have guessed that the rental prices would track the rack rate. I think some people have extra points that they bought now because prices have gone up and they feel they will need them in the future. Meantime they can rent the points and this effects the supply and the rental price.