Yeah, there are reasons why literary agents and publishers (commercial, trade publishers) do things the way they do.
One literary agent friend of mine explained a while back why she sends only a bare-bones rejection letter: to prevent getting into a long, unfruitful, and potentially acrimonious back-and-forth with the disappointed writer.
As I edge toward more serious publishing than I have done before -- only edge into it, mind you, and not with plans to overextend myself or my finances -- the more obvious it becomes that it is essential to require a a basic query (short and to the point) or at most a sample + synopsis + summary of the would-be author's promotional plans and platform(s). The fact is (and here I am borrowing a riff from another agent friend), I am going to reject most queries/proposals, and I want to do it quickly.
If aspiring authors want to get into more of a discussion (post-rejection), it will have to be on the clock with a nonrefundable retainer paid (and check clearing) in advance. If I am going to even think seriously about publishing a book (normal, royalty-paying arrangement in which I pay all publishing expenses for the book) I need to be sure that (a) the author is someone I can work with productively and cordially, (b) the author can in fact write well enough for publication, (c) the manuscript meets a reasonable standard for publishing BEFORE I even commit to editing it for publishing, and (d) that there is a reasonable, demonstrated likelihood that the book will sell enough copies to readers to turn a net profit (considering both my out-of-pocket costs and my time/effort/opportunity costs).
Too many folks have completely unjustified expectations about their manuscripts, and some quickly become time sinks if allowed to do so.
A few years of learning experiences have had results.