It's pretty interesting when you step back and think about why it might be so landlocked, relative to the other parks. The park was purpose built as a working studio theme park - my belief is that the original Imagineers on the project probably did not anticipate it being anything other than that (but maybe they did, idk). Therefore, they felt comfortable keeping the park within its original borders as much as possible, even to the point where backstage, offices, etc. were built nearly on top of it. So to your point, they're in a pickle.