I don't think the authors get paid either. So, no pay to authors nor reviewers. Does the editorial board get paid? Perhaps not.

> > That process costs money because it takes people and time to do it well. Journal subscriptions are often not enough to recover those costs.

Some of the items left to consider here are actually putting together the reviewed papers and publishing them. I would say the cost of these two items has gone down with the extended use of computers over the last 3 decades.

What other items are left? It would be interesting to know.