Not all of these theaters are profitable. Many of them have special arrangements with municipal government (government secured loans or $1 rent) on the theory that these institutions serve some public good not unlike parks and playgrounds.
While I did specify theaters sort of like I expected a whole theater complex to be devoted to it, the more common example (at least around me) is for theaters to devote a portion of some theaters (as in "screens", the "theater" terminology is long past the point of being savable as referring to one distinct thing) to running specialty programs. For example, a weekly horror series where a couple showings a couple nights a week are Hellraiser this week, and Nightmare on Elm Street next week, and there's posters on the wall advertising the schedule and there have been fliers out for months outlining the schedule.
Theaters do that not just because they have arrangements with local governments, but because it's profitable. The way the theater industry works (or at least did when I worked in it at the entry level twenty years ago and had it explained to me) is that new releases have about 80% or more of their ticket sale cost go to the distributor/producer, and the rest the theater, and that percentage goes farther in the theater's favor every week after release (making movies that draw crowds for a long time much more lucrative). That's why concession purchases are so expensive, it's where they make a lion's share of the profit.
Older movies are likely much less costly to get and run, and could also possibly be offered to patrons for cheaper admittance. Concessions, of course, cost as they always do, and they still make that money. I suspect in a lot of cases, theaters might turn a better profit offering tickets at half price for older movies, making more money per ticket and for concession sales for each admittance, as long as they can fill the seats.
Things like that are what appeared to be going on in my area prior to the pandemic, where they would do a cult film series and have the 7 PM and 9 PM showings on Thursdays devoted to the cult film of the week (not sure if they ran one or two screens for it, possibly depended on attendance and how good the other movies where doing on the 14 screens it has).
That's interesting, because Disney is already known for stopping streaming to support limited theater releases during times of the year. For example, I recall there being a big deal that peoples digital purchases of a Disney title on Amazon were blocked for a few weeks/months while they released that film in theaters again around the Christmas holidays. I'm not finding the links to that, but I definitely remember it being a thing, and discussed here.
My guess is that they might restrict or increase cost of purchase for some things (while allowing streaming, which they can limit at any time), but also them make them more likely for strategic rerelease to theaters.
If that promotes more theater showings of these and also helps keep theaters around, I'm not sure it's that bad of a thing (even though blocking digital purchases is a dick move in general)
