Put another way, that means that if you eliminated all profit from costs, you'd cut the price by only a third (not to a third). That's still hundreds-to-thousands of dollars per article.
No, it'd only cost so much if the alternative did the same thing, and that would be a foolish thing to do. It costs a lot of money to restrict access to information: you have to print lots of paper, use digital rights management (DRM), have an army of people to negotiate and manage expensive contracts with libraries, and so on. You may want to write and maintain special search engines. You also have to employ an army of lawyers to sue anyone and everyone who has the temerity to share scientific research (even though the publisher didn't pay for the research to be done in the first place), as well as try to track down those evil people who dare share publicly-funded scientific work.
An open access journal doesn't have to do any of that. They have to have some editors do final editing (who get paid), a website where they post the article, and they'll probably pay a CDN (so the website doesn't even need to be very fast). If they're smart they'll create a static (generated) website, which is extraordinarily cheap to maintain today. They don't need to create paper copies - if someone wants a paper copy, that individual can print it. They don't need to worry about the massive overhead of digital rights management (DRM) systems, because they don't need them. They don't need to negotiate expensive contracts with libraries (they still have to negotiate small contracts for editing and such, but small dollar amounts are easier to manage). Normal search engines can use their data directly, so they don't need their own search engine. You don't need an army of lawyers to punish the sharing of scientific results that were paid for by society; you don't even need to track down those people who were sharing scientific results. An open access journal needs reviewers, but they are already volunteers, so that wouldn't change.
For-profit publishing requires a tremendous amount of overhead that provides no value to society. Publishers do it because they can do all that and still make a giant profit, and they can just pass all those costs on to society.
More than that probably. At 36% margins you don’t really have to worry about cost efficiency - there’s probably a lot of cost savings to be had hiding behind all that free cash flowing around (and if that 36% margin disappears, it won’t take long for the CFO to find them).