“What do editors do?” I asked my first literary agent, having established that it was not, as I had first thought, copy editing. I was very young.
She was an editor by training, temperament and still, occasionally, practice. “Teach you to write,” she snapped.
Over time I came to see that she was right, in one way. They intend to teach you to write what their employer desires to publish and/or knows he can sell. And they want an end product that will do just that.
This is how I think modern editing evolved.
Editors Keep You Legal
Back in the day when printer Samuel Richardson was writing Pamela to keep his presses busy, nobody edited fiction. Printers could be prosecuted for content, so such editing as they did of their clients’ work aimed to keep them out of the law courts. Fiction? Not a risk.