Here is where statistics get weird. If I have a hotel with 500 rooms and a 90% occupancy rate, I have 50 empty rooms. I then go on a massive expansion kick and end up with 20,000 rooms and a 79% occupancy rate. Now I have 4,200 empty rooms. One might be aghast at that number of empty rooms, but I'd rater be in the second position than the first. Occupacy rate is never going to be 100% and the proprietor doesn't expect as much. 79% is pretty darn good, especially when you account for mid-week during the school year when there aren't any holidays or vacations going on. If you can account for an average of 79% occupancy, you take that and run with it.
But it isn't "lost" if you never had it. Perhaps it isn't "realized" but it isn't lost. Disney cannot go from 10,000 hotel rooms to 25,000 hotel room, fill 79% of those rooms, and then step back and say that it is losing revenue because it has some empty rooms. Instead, it has to step back and crow about the fact that it is now filling 20,000 rooms, which it was never able to do before. Besides, your math assumes a 100% occupancy rate which is not the realistic goal of any hotel chain that has 25,000 rooms. It might be their pipe dream. But not their goal. Bump the 79% up to 85% and you capture $180M more, not $550M more.
But it isn't "down". Disney has never, to my knowledge, had an occupancy level of over 20,000 rooms per night, on average, in any given year. There are more occupied rooms now than ever before in terms of net rooms rented and net people on property. Percentages are the wrong way to look at revenue. And there is one and only one proven way to boost occupancy rates, and that is to lower the rate of the room itself. (Free dining can do that as well, because the overall balance of high room rate plus free food does, at some level, equate to a cheaper room plus out of pocket food costs.) Gimmicks, limited time magic, early hours, or what have you, will never have the same impact as taking that $550 room at the Yacht Club and pricing it out at $275 where it belongs.
All that said, I am not sure what the point of this is. My earlier post was simply a demonstration that Disney is not now, has not in the past, and never will ostracize its off site guests. It needs them too much. Even at 100% occupancy of 25,000 rooms (which cannot happen), the total number of guests that that contributes to the parks is far less than half of what Disney wants in the parks on a given day, especially a busy day. 25,000 full rooms is fewer than 100,000 people. If 85% of those people go to a park on any given day, that is 85,000 people. That isn't close to what they want to come through the turnstiles. So they will, and have to, treat off site guests in a manner that will get them into the parks.