It's not about what they want for the 50th "annierversary." It's about what's socially acceptable as a result of the pandemic, when many folks can't go to the theme parks. Especially if we're not all vaccinated by then, which is highly unlikely with the number of kids who visit WDW.
That's what I get for typing on a phone. There is some doubt as to whether we will ever seek to vaccinate children, and whether we need to.
You can likely reach herd immunity without vaccinating kids.
But putting aside epidemiology, looking at what is socially acceptable..
If the State of Florida, come September, is down to 3 deaths per week and 50 new reported Covid cases per day, statewide... will people voluntarily continue to go along with strict social distancing?
(IHME currently projects to May 1 -- They project by May 1, Florida will be down to 10-20 deaths per day. Reasonable to see it dropping much more by September)