Please tell me where exactly could they put that third park? They had to knock out half of Downtown Disney to try to put up a 4th hotel only for the plans to be scrapped.
Maybe Garden Grove, using Tax Incentives from the City.
Or maybe in Irvine, as part of the Great Park project, or Tustin....
Look, Disney's options in Anaheim are very slim. While building multiple Parking Structures (Pumbaa, Simba and the Ball CM lot for starters) will open up some land, to get the Toy Story land, which is permitted for farming, with a temporary use for parking converted will be close to impossible. And the Katella CM lot is not big enough for a Third Park.
With the passing of the ALWI, plus California's changing laws, no way Disney will invest more than finishing up the scheduled east side projects at Disneyland and DCA, along with parking structures. Maybe in 10 years they might look at a 4th Hotel in Anaheim. (Garden Grove might get one if things look good financially with the city's incentives).
I wish I had better news. The Resort area will keep building more Hotels, with more Convention Business, Galaxy Edge visitors, and the 2028 Olympics (Anaheim is one of the host city, with the Honda Center being a venue). All good things for the city, and Disneyland and California Adventure will keep bring in guests. But the Walt Disney Company will take it desire to build a new park to Florida, Internationally or a State with lots of tax breaks and other incentives. And that is just Business.