I don't see how increasing supply brings prices down at Disney - they'll hike the price now to fund it, then they'll hike prices again to control attendance.
Buy Disney stock.
Why raise prices on consumers when you can fund a new park with the $12.6 billion in profit they earned in 2018?
Edit: I'm not the most fiscally-savvy person, so it would be cool if someone explained why I might be wrong rather than just hitting the downvote button and walking away.
I wouldn't be shocked if a lot of reasons that failed to get off the ground are the same reasons holding back new parks in north america.