You're right: Journals don't do those things, publishers do. Even PloS, open access & no subscription fees, has nearly 500 employees and an editorial group for each area, which are paid. Search up their salaries, you'll fine them. (They charge about $2000 per submission to the authors. Picking at random, the most recent issue of one of them had 80 articles, or $160,000)

Or look at the editing that Elife professional editors perform in addition to other peer reviewers: detailed feedback on the manuscript for the authors, including requests for revisions and suggestions for improvement." detailed feedback on the manuscript for the authors, including requests for revisions and suggestions for improvement

Maybe poor quality journals don't do this sort of thing, I'm not familiar with them & their economic models.