Yes, I think having a sliding scale is important. I reduce my rates whenever I feel like I’m working with a manuscript that doesn’t need as much handholding as someone else’s rough draft might.
I absolutely agree with you on everything you’ve said. It’s a huge challenge trying to balance wanting to provide a good service and making it affordable for authors on a low budget. And I think this is true, like you said, for general employers when they’re negotiating salaries. It isn’t the author’s responsibility to cover their personal expenses, but my hope in the editor-author relationship is to try to get both sides to understand why things work the way they work. There are insurmountable challenges on both sides.
The best answer, I think, is to find an editor that’s skilled who isn’t in it to make the most money possible. I’ve worked (as a managing editor) with editors who charge up to ten cents per word, and it almost becomes prohibitive if they haven’t focused their business on attracting wealthy authors. The reality is that many of us are trying to build from a pretty low financial foundation, so those five- and six-figure contracts come few and far between.
This is the exact reason why I tried to start an editing subscription service, but it’s proven to be wildly unpopular (in my opinion) because clients don’t like to sacrifice deadlines. Sometimes it seems like it’s a no-win situation.