I think what
@ParentsOf4 is saying makes sense, and they have certainly provided evidence that suggests a new one is required.
Must admit, though, I am with those who think they need to build out their existing parks and try to address overcrowding through increased capacity. It would be nice if their next big initiative was to build capacity across the parks, identifying areas that were basically lying vacant and developing a program of smaller attractions with a few E-tickets sprinkled in. It would seem more efficient to essentially add a new park's worth of capacity across the resort that used the existing infrastructure.
I suspect a concern for Disney is also the greater difficulty they have to adjust to changing circumstances the bigger the resort gets. Hotels are a little easier to close in whole or part, but another theme park and all the infrastructure to go with it represents more exposure in the event of a future pandemic, economic downturn, war, etc. Wasn't this the reason Steve Jobs suggested to Iger they should sell the parks?