Editors don't cost much, but publicists are expensive.
Good editors are expensive.
Another other route is via an agent. But these routes are overlapping now more than they used to. For example, it is not uncommon for publishers to obtain books from publicists the way they previously did from agents.
I've never heard of a publisher acquiring a book from a publicist. Do you have a few concrete examples you could share?
Book scouts are a different matter, of course. Might this be a difference of terminology rather than opinion?
They want to see the track record of the writer--not just how they write but how they self-promote.
Every week, probably every day, good publishers sign up writers who have no clue about how to self-promote. Publishers want good books: an author who can also self-promote is a bonus, but it's not essential.
I know agents who have left the business because they can no longer compete in this environment.
So do I. They were mostly not very good at being agents, though.
My sense is that this is the direction things are headed. Not to say that I personally like any of this--just that it is a reality!
I--and many of the literary agents I know--feel that things in publishing are changing, but then again, they always have. I think many agents will offer more services to their author-clients as time passes: but I don't think that any reputable agents will start charging fees to their clients just for representing them. That is a direct conflict of interests, and I can't see any good agent working in that way.