And isn't another part of the equation, how will Disney adjust ride/services capacity to match the crowds. I mean, if the crowds are "smaller", then that makes for a nice experience with literal crowds and moving around (especially post Covid), but will it makes lines shorter? Perhaps not.
Heck, we were there in March (crowded) and couldn't get a Dole Whip in AK because the concession shut down about an hour before park closing. I mean, we survived obviously, but they can always adapt offerings to smaller crowds.
Absolutely. For that matter, we almost always go in January and couldn't get anything to eat for about the last 3 hours before MK closed because all but one QS place closed. The only one left open was swamped.
Plus fewer people wouldn't mean shorter waits if - as suggested - they are only loading ride vehicles a quarter or half as full and having to stop to sanitize vehicles every few runs. For example, BTMRR has a ride capacity of 2,400 people per hour if both sides are running. Let's assume they keep both sides running but only load people into every other row, so you're down to 1,200 people per hour. They need to sanitize the ride vehicles more often, and you can't double-load the queue at the loading area (e.g. only one group can stand on 'row 12', instead of the people who will ride next AND the people who will ride after them), but that gets tricky with roller coasters because the timing is very particular. So assume that they are only running 4 of 6 possible trains at a time. That takes capacity down to 800 per hour, or 1/3 its usual capacity.
So if the parks are operating at 1/3 capacity, that means your wait time would be the same for BTMRR as it would be during your regular, non-COVID visit, right?
WRONG
Because 1/3 capacity is not the same as 1/3 of the usual park busy-ness level. So if you usually visit sometime other than Christmas week or Easter week or 4th of July, you're not seeing the park anywhere near capacity. The average number of daily Magic Kingdom visitors is about 56,000, or barely 1/2 of the stated capacity. Meaning if ordinarily your wait on a particular day/time for BTMRR would be an hour (2,400 people in line in front of you), and park capacity is at 25% (so 1,200 people are in line in front of you at BTMRR), then your wait would actually be 90 minutes - or 50% longer than it would usually be even though there are fewer guests in the park.
(This scenario makes a lot of assumptions that aren't quite precise and assumes that the distribution of guests through the park and choice of rides would be consistent before and after the virus, that the parks do actually reach their capacity limit for the day during all of this, and that there aren't additional time factors involved like a longer loading time due to use of remote queues or shutting down the entire coaster once an hour to deep-clean every car, etc. But just as an illustration.)