I seriously doubt that anymore resorts will be built in the next five, maybe even next 10, years that aren't part of the Vacation Club brand. At some point, I am sure they will finish Pop Century though.
After 9/11, Disney came to a hard realization. They had overestimated the continued expansion of the tourist market. They had just completed the first half, approx 3000 rooms, of the Pop Century and had started work the second half when the rug was pulled out form under the Market. Not only would they not be able to fill the first 3000 rooms, but they also couldn't substantially book several other resorts. Thus we saw the closing of the French Quarter and the shuttering of half or so of Riverside to eliminate about 2000 rooms from inventory. We also saw bookings at the Institute decline to the point it was a ghost town, effectively eliminating 500 more rooms. At one point, part of Coronado and Caribbean were also closed of for rehab.
All of these closings still left Disney with somewhere in the neighborhood of 17000 rooms to fill, out of the approximately 23000 rooms they owned and operated. It is widely known in the hotel industry that you need to have about a 65% occupancy rate to meet your costs. That means Disney would need to fill about 15000 rooms every night.
The rapid change in the economy also forced Disney to see the increased exposure they had to bad economic times and other events. It made total sense in the booming 90's to add rooms. After all, why let all of that revenue go to Marriott, Holiday Inn, etc. People weren't coming to visit Orlando; they were arriving to visit Disney World. I guess you could call it the One World, One Vacation strategy. Give them everything in one place, so that guests didn't have to venture outside the 47 acres to spend a dollar.
Of course that all works fine so long as demand is very high and there are plenty of tourists to go around. But when things go wrong, like economy and world events, and the market drops, you and the other operators still need to fill 65% of the available rooms to turn a profit. That gets considerably tougher as everyone is clamoring for the same limited number of customers.
The bonus for Disney is that they could close resorts, not open new resorts, and shuffle folks around to minimize the impact. It also allowed them the down time to rehab, or in one case, remove those properties which needed updating. It really wouldn't surprise me to see each of the All Stars go in for a rehab after POP Century opens in December.
The great thing about this supposed change in strategy is investment money is freed up for other uses. The best way to fill 23000 rooms is to give people a reason to come and visit again. A new ride here, new spectacle there, and new shows are great ways to garner the interest of those folks who are marginal about coming to Disney vs going elsewhere for Vacation. As we have seen already, the rumors have quickened about new attractions and activity. The old adage, "where there's smoke, there's fire" would be appropriately applied here. While not every rumor will become reality, enough of them will to pique the public's interest in vacationing at WDW again.
Note: Hotel room estimates are just that. The information was gleaned from various websites and should be reviewed with the understanding that there may be a margin of error involved.