According to
http://www.disneypix.com/Resorts/ResortFF.htm:
Total Rooms 25,585 (adding Disney operated rooms + Disney Vacation club rooms)
Disney only allocates so many rooms for each discount, including
AAA.
I think only Disney can answer this question - but I bet it is 70-30 or 80-20 or so, with more people paying rack rate than getting a discount.
Look at it this way - there are thousands of travel agencies out there, and how many do we hear of that do what companies like DU and Dream Come True Vacations and Small World do? Most of your brick and mortar agencies and AAA agencies have never heard of a discount code - let alone pro-actively try and apply them for their clients to save them money.
How many people see the $1500 Magic Your Way promotion for a family of 4 and think that that is the best they can get? and then call Disney and just book it?
I have a friend that I work with who goes to Disney every August with her family of 4 and stay at the Grand Floridian for a week - in a Lodge Tower room - and up until this year, they paid rack rate!!!!!