I'm getting relatively sick of the "DISNEY IS COMING TO AUSTRALIA" people popping up on the forum over the 3 years I've been here. Disney building a park on the Gold Coast, let alone Australia, would make little economic or business sense.
One of the things that puts off big theme park companies setting up on the Gold Coast is the small population of the area itself. Even if you add Brisbane and the rest of South East Queensland to the number, it still adds up to less than 4 million.
The two theme parks that Disney consider as their smallest parks, Hong Kong and Paris, both have population counts close to 7 million in their city metro areas. For those that don't know, Paris, despite it being open for 25 years, has never made a profit. Hong Kong, while it had a slow start, is picking up steam in recent years, with aggressive expansion (and a gigantic expansion plan in the years to come, including replacing half of Tomorrowland with Marvel attractions, a Frozen land, and a Moana area.)
While the Gold Coast's tourism revenue is high for Australia, in comparison to other cities that Disney parks are built in, it is miniscule. Take a look at Paris and Hong Kong, for example.
Paris, while tourism is declining greatly, is still among the world's most visited cities. The tourism revenue from Paris alone consists 7% of France's GDP, which in 2016 was 2.465 trillion USD, which equals about 3.1 trillion AUD, meaning the tourism revenue of Paris that year was $21.7 billion.
Hong Kong's tourism is also quite strong, accounting for 5% of its GDP, which was 320.9 billion USD, or 405 billion AUD, meaning that the tourism revenue of Hong Kong was around $20 billion.
By comparison, the Gold Coast's tourism revenue is tipped to reach just $7 billion by 2020. While impressive, it is tiny in comparison to the cities where Disney want to set up in.
That's why Disney won't be coming to Australia - for a while. Just my 2c.