WDW’s problem all comes down to ride-to-room ratio.
Universal has 2 theme parks, both loaded with E-ticket attractions. Universal has 2400 onsite Deluxe Resort rooms. The 3 Deluxe Resorts are not owned by Universal; they are owned by Loews. Universal gets a cut of that and sells Express Pass to supplement income. Universal is in the theme park business.
Disneyland Resort (DLR) is similar. It has 2 theme parks, lots of attractions, and 2500 onsite rooms. DLR's main revenue comes from the theme parks. DLR also is in the theme park business.
WDW has one outstanding theme park and 3 that many treat as half-day parks. However, including the Swan, Dolphin, and Shades of Green, WDW has 31,000 rooms!
Many of those rooms sell for hundreds, even thousands of dollars per night.
Few realize it but WDW is no longer in the theme park business; it’s in the hotel and timeshare business.
At WDW, the big money is not to be found trying to convince guests to pay extra for FP/FP+, it’s in getting those hotel rooms filled!