In the traditional model, journal editors and the referees do most of the work, for which they are usually not paid.
> The publisher's editors organized individual journal editors, helping to find new ones when one left, keeping them on deadline, etc.
Most journals have an editorial board and they are generally much better in finding new journal editors because of their contacts in the field.
Keeping deadlines is only important when you are printing separate issues. When you have a journal that consists of an electronic stream of articles, deadlines are not a serious issue.
> The publisher's editors processed submissions to the journal working with criteria set by the journal editor to perform an initial review for off-topic, low quality, or otherwise flawed submissions.
This can also been done by the journal editors. AFAIK all rejections I have ever seen were done by journal editors.
> Other publishing staff:
>-performed proof reading & copy editing
>-did the layout & type setting
>-They used professional color matching labs for all color images, which itself was $100/image (tech for this has probably changed and made it cheaper) [0]
>-They managed every aspect of the actual printing of the journal, dealing with printers, reviewing proofs, coordinating a final round of review by the journal editor and authors.
>-warehousing copies for expected distribution over the life of the journal, re-prints when something was more popular than expected, and all order fulfillments to individuals & libraries. [1]
>-They handled all of the financial logistics, from collecting subscription fees to paying the journal editor and handling royalty fees for decades after a journal was printed & back copies were purchased.
Most of these tasks are no longer needed when the journal changes to free electronic publications.
Fortunately, that seems to be increasingly popular.