Publishing as we understand the idea came about at a time when physical scarcity was the limiting factor in dissemination of copies of works. That time has passed. We're in a completely different world now. The elevator operators and buggy whip manufacturers of the publishing industry would like things to remain the way they have been.
I don't think the issue is the scarcity of copies, but rather the scarcity of artists. Not just anyone can write a book that people want to copy, and we should encourage and reward those that can and do.
Filtering the crap is now orthogonal to the concern that, historically, information dissemination has been tied to physical scarcity. Those concerns ran together because it cost money to publish something. It doesn't now.
We can come up with new models that compensate creators more directly. We can also come up with models that don't involve effectively killing any ability to build upon existing culture in the time-scale of a human life.
What came before isn't how it has to be, except that the interest that profit from the current system want it to remain so.