it's very simple, each guest is a $$ per person, more specifically, profit per person for Disney. I'm feel confident in stating that onsite guests yield more profit per person, per day than offsite. A) profit from the resort, B) potential increase in discretionary spending. Disney has morphed from a having a few resorts to a full fledged resort destination. The 'build it and they will come' is in full effect and Disney is smart to expand there offerings. They never claim or set out to be the 'cheapest' destination or amusement park, that's what carnival's and six flags is for. So why should they also be expected to be the cheapest lodging option? from what I can see, the great divide for lodging comes for a party of 5 or greater, there definitely is a huge jump in cost as the 5th person in effect doubles the cheapest lodging option. what will be interesting to see is whether over the next decade Disney begins to offer more competitive options for parties of 5 or greater. We stayed at AoA cars suite for a party of 5 last August and it was same price as 2 value rooms or cabins (not including cart rental). it seems to me that the party of 5+ is an area they can work on. IF that demographic is a large enough contingency that can yield profit away from offsite options, i'm sure they will.
What would also be interesting is if they ever come up with an option for larger groups, say 12 or more where maybe there are dorm like rooms to accommodate large groups, AKA youth groups, etc....
and I am also all for onsite guests getting better perks such as advanced FP+ bookings. Universal includes front of line pass for their onsite guests at 3 of their 4 resorts, anyone BBQ'ing universal for that?