Why lower quality? The money doesn't go to authors, editors or peer-reviewers.
Copy-editors are expensive, and paid for by the researchers, not the journals.
My spouse is an editor at an academic journal in her field and does some of both. In papers selected for publication, she does exert editorial input. In terms of remuneration, it is a compensated position; but how the money flows between the academic society, the journal and Elsevier, that part is lost on me.