And like traditional publishers there is still a role they can play, edition and synchronisation of anonymous review remains an important element of paper publication.
https://docs.google.com/document/d/1HD-BEaVeDdFjjCNFkb0j3pvw...
The work itself obviously is not[0], but you need somebody to synchronise that stuff, especially to ensure reviews remain anonymous (to paper authors). This must be handled by a third party.
[0] not entirely true for edition, publishers generally employ a number of editors although these editors usually have a solid science background for obvious reasons.