[michaelmior]

The publisher does often assist with coordinating the peer review process which is a nontrivial task. I'm not saying this in itself necessitates everything else surrounding the publishing ecosystem, but I don't think it's accurate to say the publisher does not contribute.

[jampekka]

In my editor experience the assistance is minimal at best. Editors (almost all upaid) assess suitability of manuscripts, find the reviewers and handle all communication.