Multiple outlets publication Perhaps, it's a naive question, but I'd like to have some clarification of my own thoughts on the subject. I'm curious about what is the rationale or need of 1) transferring copyright from authors of an academic artifact (paper, chapter, book, etc.) to a publication outlet and, consequently, 2) an inability for the authors to publish their work via other publication outlets.

I realize that the above is somewhat questionable from the ethical perspective of accumulating publication credit for essentially the same work. However, I think that this problem has an easy solution (which I've seen used by some people) - specifying in CVs and other materials that paper B, published in journal BB is the same (or lightly changed) as paper A, published in journal AA.

Assuming that the ultimate goal of scientific research is to enrich the human knowledge on a global scale is much more important than the above-mentioned slight ethical concerns (which can be easily alleviated), publishing scientific artifacts via multiple outlets IMHO makes quite a lot of sense from the perspective of exposing the work to a larger potential audience, which, ultimately has a positive effect on scientific research knowledge sharing and distribution.
Publishers have to eat too, and if you can take the same thing you published with them and publish it again with someone else, who will buy it from them?  Their argument is that they invest in the publication process and need to get a return for it.  I have some skepticism about this argument (these days, universities could pretty easily and cheaply operate open-access online publications, etc. etc.), and am personally a much bigger fan of open access, but that's the standard argument.

N.b. there's also a (smallish) benefit for authors in having a central place to go for things like reprint requests.

Also, many publishers these days are ok with a certain amount of republication.  For example, most copyright transfer agreements I've seen for journal articles explicitly allow the author to republish in a larger book, e.g., a collected papers book or a follow-up.