[Worldwalker]

It's a buyer's market. There are more manuscripts being offered than any given publisher could possibly buy. They have no need to teach authors how to write because there are plenty who can do so already, and who will do so. I'm sure if publishers find the supply of authors drying up, they'll do more to improve the quality of the ones submitting to them, but right now, the problem is one of excess, and there's no business reason for them to enumerate why any given manuscript doesn't meet their needs. There are plenty that do.

Taking it to extremes, publishers could improve the future supply of submissions by running writing classes in all the schools. They don't, though, because they don't need to. They have all they need already, so they have no reason to add an additional expense.

Also, there's the matter of opening the door for rejected writers to argue, argue, argue about whether those reasons for rejection really apply to their manuscript. There is all the potential drama when two different editors reject two different manuscripts and the authors of one or the other compare notes. There is the potential of attracting legal problems (which should be laughable, but in today's climate, it's not). There are, in short, innumerable down sides, from the publisher's point of view, to saying more than "no", and very few up sides.

Also, there's the matter of honesty. While I've never read slush for a living, I have seen examples of what comes in unsolicited. If you want a good example, read 10 random fanfic stories from one of the better (that is, less trendy) fandoms. Those check boxes would be things like "make your story not suck", "make your story notreally suck", and "burn your story and hide the ashes; you cannot make this not suck." Snark aside, from what I've seen of slush, the vast majority of manuscripts are rejected for things that it is not a publisher's job to teach a writer, and which, if the writer is unable to learn on their own (and before submitting it) leave open the question of whether this person should be a writer. The ability to read submission guidelines and submit to publishers of the appropriate genre is something of a shibboleth. Yet people do send romances to science fiction publishers, science fiction to literary publishers, literary novels to thriller publishers, thrillers to non-fiction publishers, biographies to fiction publishers, and so on. Incessantly.

So that gets back to the slushpile reader needing to take more time for any given manuscript. Instead of "yes" or "no", tossing it in the accepted pile or the rejected pile and moving on to the next, the reader would need to take the time to quantify exactly what is wrong with the story, both in absolute terms and in relative terms, and make sure it's defensible from the inevitable angry reply, and possibly from legal action as well. From the publisher's point of view, that's spending money to no good end. Remember, they don't need to teach potential writers how to write; there are enough people who already can to fill up their publishing schedule. And there's no guarantee that such a person, once educated, would submit to that publisher anyway. They might be working for free to assist a competing business. In short, there's nothing in it for them.

As badly as publishers can get things wrong outside their area of expertise (DRM in particular) they do know how print publishing works, and how to do it. They've been doing it for centuries. They send the form letters they do because that works for them, in a business sense, and they are businesses, with any business's need to maintain supplies and markets, and make a profit somewhere in the middle.

(by the way, except to the advertising industry, "quality" is a noun)