At least in theoretical computer science these tasks are all done by the volunteer conference organizers.
It's possible that this is different than in fields that primarily publish in journals, but it certainly seems like the volunteer approach works just fine.
I have also never seen anything getting improved typesetting or prose. The reviews may reject based on bad writing, or the journal may reject due to latex warnings, but never more than that.
I wonder what journal you work for?
Sometimes conferences pay a publishing company to do the review process for submissions, by the way. I'm not sure that your submissions are actually getting processed for free by conference volunteers.
I'd rather not disclose details of my employer, sorry.
> just happens that the resume byline "conference organizer" is valuable enough in that field.
Being editor of a journal/PC chair is a valuable thing in any field, not just CS.
Well, I'm sure, because I also review for the same conferences and journals that I submit to!
The problem is about the business practices of the big publishers - asking huge amounts of money for access to journals, forcing universities to buy bundles of journals, to get access to interesting articles they also have to subscribe to stuff they don't want, and so on.