Samantha England
Scribe
As someone who published my first book (non-fiction) traditionally, let me clarify this misconception. In this age, the author pays for the proof-editing. The publisher might suggest an editor, but it comes out of the author’s pocket. The only editor the publisher paid for was the copy-editor, who formats the book for print. By the time it gets to them, the prose had better be flawless, or you can expect them to reject the manuscript and send it back to the author to go find an editor.
The only real pro to traditional publishing is the marketing (I’d include cover design as part of that). That’s it. Depending on the publisher and your genre, their professional marketing strategy may or may not be something to brag about.
That's interesting, as I'd been pointed more towards the explanation that, should your manuscript get purchased by a publishing house, it also gets handled by an in-house editor. That is, of course, after it's already been revised and edited before it even gets seen by a literary agent who would then solicit that manuscript to said editor of XYZ Publishing House. Revising and editing is always a good idea even if you don't plan to query a literary agent and instead send it straight to the publishing house (though I do know that the majority (I think) of major publishing houses won't accept manuscripts without a literary agent to solicit them just because of the sheer number of submissions.