With Villains and Cars, both are happening at the same time. More acreage that's currently not part of the park is being used within the park.Hence why Disney needs to use its blessing of size and EXPAND not REPLACE
Same with TRON.
Same with Monsters Coaster.
Same with Guardians and Ratatouille.
Same with SWL and TSL.
Same with Encanto.
But there's also a limit to expanding: A giant swamp. Some of which is designated as preserved wetlands, which, if Disney wanted to build on would require purchasing acreage many times bigger elsewhere to designate as preserved wetlands (which is what Disney did for the DHS expansion).
And even where they can readily build, it's still a swamp that needs drainage and designation of nearby retention/detention ponds.
The blessing of size is being used up. This is why all new hotels/DVC are towers and not sprawling compounds like the Value or Moderate resorts.
They do have some buildable land, but not readily connected to existing parks. This is why the Cars/Villain lands require water management permits just for a laydown yard.