Except in the context of how much cash WDW generates, there’s no market for those things. Everything other than “let’s crank a ton of people through our theme parks and give them places to stay that makes that easier” has been a loser. Discovery Island, the golf courses, Disney Quest, Disney Institute… they aren’t bad ideas, they just end up being a drop in the bucket and not worth it. Discovery Cove would be a drop in the bucket to WDW - it is not a drop in the bucket to a smaller regional park like SeaWorld.