The Real "Cost" of Open Educational Resources
I will refer to your criticism by number, hoping that any updates to the list will be additive...


Criticism 1 (maintenance) is, in a theoretical sense, true, but open materials are often addressing it in their own way: with collaborative tools like github/gitlab and bug trackers that make reporting of errors and improvements easy. Meanwhile, publishers aren't always great at quality control, particularly when it would require them to reprint their books often (see, e.g., Hefferon's gitlab). For example, Serge Lang's Algebra is famous for its amount of mistakes and lack of polish, despite having seen three editions. My impression is that printed books are rarely revised to improve quality; instead re-editions often include new chapters, permute existing chapters, and try to dumb down some material so that it can fit more courses. Anecdotally, this is being done in order to make the old editions incompatible and thus scorch the used-book market; of course, intent is hard to prove in this question.
Criticism 2 (job killing) can be (and is) levied at pretty much any innovation. But this is how the world is supposed to move forward, by making formerly hard and costly things trivial and automatic! (And history, so far, has always shown that those who want to work will never run out of things to do. Getting paid for them is a different story... But medieval stasis cannot be the answer.)
Criticism 3 (pressure) is not happening anywhere around me (and I'm generally gravitating towards OA-friendly places). I have been using open texts whenever I could, but I don't see anyone pressuring me into doing that. (Students have occasionally thanked me for it, though I've more often been critiqued for not assigning a text that could be consistently read. Needless to say, with a subject properly covered by open-access texts, you can get the best of both worlds.) I suspect that intercollegiate pressure is much more a function of the climate at one's institution than of whatever is happening in publishing.
Criticism 4 (stigma) is probably a real effect. Once again, however, shifting standards are a consequence of any sort of improvement! LED lights have been stigmatizing old-fashioned lightbulb makers in just the same way. In many ways, book writing has already taken a large reputational hit before the Internet came along, and general advice in the academic community seems to be that the main purpose of writing a book is "so you can show your grandpa" (meaning that even the generation currently in their 40-50s will not see it as a particular milestone). The main reason seems to be the proliferation of books and the ease of publishing one (even with the established presses), not the advent of open access sources.


As you are asking for further criticisms, let me throw a couple in the air, although (being an OA advocate myself) I do not view them as heavily important:


Criticism 5: The free might drive out the good. I.e., if the best openly available materials are inferior to some printed books, some teachers will nevertheless pick the former for their free availability. I suspect this is a real issue occasionally, but mostly a temporary one. At least on the undergraduate level of my disciplines (algebra and combinatorics), there are usually freely available sources of the highest quality I know (when it comes to linear algebra, I even consider them superior). Finding good free texts gets harder the more advanced (and rarely taught) the class is, but most teachers don't assign bad texts just because they are free.
Criticism 6: Free resources might enable monocultures. If every lecturer has a choice between (say) 10 popular linear algebra texts of roughly equal quality, then you might expect each of these texts to have a popularity of roughly 10%. If someone writes a free text of comparable quality, you will suddenly see lots of lecturers adopting that free text purely because it is free. Subjects that are not covered in that text will disappear from classes; people's viewpoints will differ less (which is not a good thing for academia, whether or not students accept it). Note, however, that the same thing happens whenever a really good textbook comes out (say "analysis" and you will hear "Rudin"; say "differential geometry" and you will hear "Spivak"). In such cases, open access may actually disrupt that equilibrium even as publishers may lack the courage to do so.