First, as I noted in a lower comment, the physical mediums aren't long gone. Second, Publishers provide some value - they aggregate editors and peer reviewers,

First, as I noted in a lower comment, the physical mediums aren't long gone. Second, Publishers provide some value - they aggregate editors and peer reviewers, they provide copy editing and layout services, and yes, they produce actual physical copies of the journals. These could be provided by other means, but most of those involve more work for the researcher. And after reading a vast swath of LaTeX layout papers, I value their layout services if nothing else. Third, you seem to be assuming new companies aren't "disrupting the space". PLoS has been doing so for years, and PeerJ and eLife are picking up steam.