Studios is a "feeder" park that supplies early day diversions to crowds that tend to defect to EPCOT, Magic Kingdom, and Downtown as the day goes on...
Perhaps it didn't start that way - but it has evolved into that kind of model.
Simply put: when you have the bigger parks with more merchandise and food comparably available - you create the possibility of making more profit off the staff you are employing...and as they stopped short of making Animal Kingdom a true full day experience...they clearly "tiered" their two least popular parks (by attendance) into being feeders to the big money makers.
So it comes down to this: there is little reason for major capital investment and construction in studios until the parks become crowded to the point where they need more people in the park all day - and those people consume more disney on-site hotel rooms.
That is not the case - the parks are far from "crowded" to the point where they need a bigger footprint and a billion of new rides at studios. Whatever your perception is - the reality is that they don't fill up magic kingdom and EPCOT enough to warrant this.
And based on overhead and profit - the animals are far more expensive to maintain and they have undoubtedly alot higher cost to run animal kingdom. It makes more sense to add to AK to recoup costs - if they were inclined to do so. But we aren't there.
So i advise caution when "predicting" expansion at studios. Right now, they are making more bucks off toys in every toy isle at
walmart off their recent acquisitions.
Would it be nice to show us some love and put in new lands and rides? Yes of course...but the reality is this:
WDW is there, it makes a heap, people still flock to it, and the prices have been on the steady rise for years.
Why give us more when we take what you're giving already?