There is zero chance that Universal's parks collectively out-draws Disney's. Zero.
Even during a year when Disney refused to sell annual passes, and periodically refused to even sell day-tickets because the parks were at staffing capacity, the total attendance was 47M. Universal was 21.8M. Throw in the water parks and Disney hits 49M, with universal at 23.7M.
(Source:
https://aecom.com/theme-index/)
There is no way that Universal closes a more than 2x gap, even with
Epic Universe open.
If Disney doesn't start to construct new attractions in next couple of years, by 2030 the 3 universal parks will have combined higher attendance than the 4 Disney parks.
As what you currently see planned at Epic universe is just the start.
They have rights to 3 massive IPS on same level or above that of Mario/harry Potter
Islands of adventure is already in process of Zelda land being constructed.
The other 2 IPS they have secured rights for will be the real draws that finally see them overhaul Disney.
All the current office buildings and stores at studios will be removed once the new ones are built at epic universe leaving a lot of room to expand in the area behind men in black, Simpsons rights expire in 2028 so that whole end of park and extra area will be themed to Pokémon. Work will start after epic opens.
The popularity of Pokémon dwarfs everything.
One would then expect Disney would have to respond with putting the blue sky concepts in to reality, but that won't be enough as universal have left there biggest project to last namely lord of the rings being the 1st expansion at epic universe.
Studios having harry potter and Pokémon in same park out competes any Disney park for the family market.
Epic universe having a ninentdo land,lord of rings land alone out competes any Disney park even without the other lands.
Islands of adventure already fulfills the thrill seeker market and would expect universal to add another couple of thrill attractions there to cement that giving them 3 very different parks.