2021 is a major year for Walt Disney World as it marks the 50th anniversary of both the resort as a whole, as well as the first theme park found there, Magic Kingdom. Magic Kingdom opened on October 1, 1971, but if you were considering visiting the park on that day to celebrate the milestone, there are going to be some issues, as all reservation types are currently sold out for October 1, 2021.
According to BlogMickey, if you hadn't already made plans to visit Walt Disney World and made your ticket reservations, you're already too late, at least at the moment. If nothing else, is certainly shows just how far advance people are already planning. At this point Walt Disney World has released little in the way of details regarding what the plans are for the 50th anniversary day, and due to current restrictions, expectations are that things will be greatly paired down compared to whatever might have been otherwise planned, but a lot of people plan to be there anyway.
Of course, odds are that more reservations will be released at some point between now and October. If nothing else, the number of reservations currently available is likely based on current capacity restrictions, running at 35% of what the parks are capable of according to Disney, but it seems all but certain that capacity will be increased between now and October, and when that happens, more reservations will likely be released.
Still, the fact that reservations are currently gone certainly shows that demand is high, even under current circumstances. Any new reservations will likely be snapped up just as quickly as they are released. This is also likely a signal of things to come. All indications are that the reservation system that's been implemented to handle reduced capacity won't be going away once theme parks are able to welcome back all guests. This means that in the future days like special anniversaries, new ride openings, or other big moments , if they're big enough, could potentially see theme parks get "sold out" months before the event. It has the potential to make vacation planning a bit more of landmine. For every Walt Disney World fan who wants to be there for a special day there's a vacationer who just wants to visit the park and isn't even aware it is a special day.
And while there will almost certainly be something special planned for Magic Kingdom on its 50th birthday, the fact that the park will almost certainly not be at full capacity means that whatever was on the agenda may not happen anyway. A special parade or fireworks show would seem unlikely as there's no indication that parades or fireworks will even be happening. Perhaps that will change before October, but it does seem clear that 2021 is going to be another year of just getting by for Walt Disney World.
Of course, since Walt Disney World's "50th year" starts in October, maybe in 2022 we could see more 50th anniversary celebrations taking place as things get more back to normal.