Disney's not too shy about their innate desire to reach into your wallet and take every last dollar in exchange for their "once in a lifetime memories" (remember, you're allowed to harshly judge that which you love.
) If the suits that run WDW thought they could turn in a profit by having the parks open 24/7, they'd do it. As it is, they supposedly lose money by having the park stay open for extra magic hours, but it's a loss-leader, and they use it as an incentive to get people to stay in WDW resorts and do more eating and shopping on-property.
Quote from head mouse:
Well, just like any other 24 hr place, certain sections/attractions would close at a certain time for maintainence.
ie: if Haunted Mansion needed maintainence, then at 12:00 they would close it to do their work, and re open it the next morning.
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A theme park like WDW isn't exactly the same thing as a 24-hour supermarket or pharmacy or diner or drive-in movie theater. ALL the attractions and restaurants & theaters and kiosks need time and (I would think) a large staff of people to make sure everything is up and running for the next day. It's not like there's a list for maintenance that says
1-2: Clean up Tomorrowland
2-2:45-Toontown
2:45-3:30-Fantasyland
and so on. There's stuff that is getting done in all of the lands, all of the time. I would guess that overnight cleanup is run almost like a military operation, to ensure things are done on time. And having tourists in the park is bound to get in the way of that operation. I'm sure, as extensive as the underground tunnels are, they need the walkways overnight to get people and items where they need to go.
In short, I'm sure the time that it takes to adequately clean and prepare the parks are already factored in to the schedules, especially when it comes to peak times where extra mgic hours might mean that there's only 4 hours or so to do everything. Having it open 24/7 means that visitors are constantly exposed to the nuts-and-bolts side of the business, where the "magic" such as it is, is lost. No grand ceremony to announce the opening each day. More security to make sure an all-night WDW doesn't attract the wrong kind of element (or that tempers frayed by being up all night doesn't wind up into fights). It's all far more trouble than it's worth, and I'm sure, if WDW thought there was an upside to being open 24/7 they'd have done it by now. Sorry to whizz on your parade, but it sure doesn't sound logical, or magical, to me.