Can we justify the involvement of corporate publishers in scholarly communication

“Most academic research is funded publicly. As such, we owe it to the tax-payer to justify the way we do science as the most cost-effective way we can practically operate... before this post, I've argued that there is no justification for keeping corporate publishers involved in scholarly communication... However, there have been a few posts and comments recently, which have prompted me to ask others if they could justify the role of corporate publishing in scholarly communication. I think the first was Cameron Neylon's blog post on how little publishers understand us scientists and how little we understand them... I'm not claiming that we should do the publishing, but that our libraries should do it. After all, haven't they archived and made our work accessible for centuries? Isn't this what libraries were for... Maybe more precisely: what are the tasks that are so important that you couldn't have a commercial service provide them to libraries who store and make accessible the works of their faculty to the public at large at a fraction of the current cost to the tax-payer? What are the reasons we cannot have commercial businesses competing for (library-)contracts to perform: (transparent, accredited, etc.) peer-review organization, copyediting, illustrating, (insert the mystical tasks that justify the involvement of corporate publishers in scholarly communication...”