Disney is like any other big company in that there are executives on many different levels with different goals and expectations for their department. Ken Potrock, Karl Holz, et. al. must answer for DVC profitability. Their performance (and future job prospects) are tied to how well the DVC product sells. Period.
Staggs, Meg Crofton, Kalogridis and others answer for the performance of the theme parks.
It's no different than a company like HP where you have separate divisions selling computers and printers.
There are opportunities for synergy in these situations, but the challenge is getting all parties to sign-off on such deals. Take something like the $399 Premium Annual Pass from last year. DVC certainly benefits from that. It's a great perk for members which increases good will. Helps sell new buyers on the value of DVC. More trips for owners could lead to add on sales.
But the value isn't so clear-cut for the theme park officials. They were asked to take a $300 hit on EVERY SINGLE PAP sold at the reduced price. For a family of 4, that's theoretically $1200 in lost revenue...multiplied by hundreds or thousands of families. The challenge is trying to convince the theme park division that they'll make up the difference elsewhere.
Unless both parties can see some way of benefitting from a perk like that, it just doesn't happen.