Oh, my. This is a good one. As both writer and editor, I feel I’m qualified to answer this. Here we go…
Writers are completely responsible for their work. Why? Because editors cannot force a writer to take their advice. The story belongs to the author. The editor’s job is to point out how the story can be improved. The writer always has the choice not to apply all or even any of the editor’s suggestions and corrections.
The writer is the creator and retains full rights and assumes full responsibility for their creation/publication.
The editor is the helper and may not even be credited. That’s OK, since many editors do not get to see the final published work, and there’s always the worry that the writer has not taken our advice. Indeed, there are writers who use an editor’s services for only part of their story (usually the first or first few chapters). In such cases, the editors would much rather not be credited.
But what about the writers who complain on social media about spending thousands of dollars and not getting what they need? Here’s the hard truth - If a writer has willingly paid an editor (even if it’s someone only claiming to be one), and this person then turns round and gives them back nothing more than a proofread copy, there’s precious little anyone can do about it.
Many writers hire an editor without even knowing exactly what they need, without even knowing the difference between a developmental edit and a line edit. At the very least, understand what you need, ask around for indie writers who are happy with their editors, get the low-down from them. Word-of-mouth is great. You can get personal recommendations by asking in critique groups. Your questions are aimed at published indie writers (preferably writing in your genre/subgenre) whose work has been professionally edited to a high standard, so ignore everyone else. Be ready to ignore the people who will solicit you there.
If you’re too shy to reach out to others in groups, then find well-written (i.e. well-edited) indie books in your genre/subgenre. Check to see if those writers thank their editors on their Acknowledgement pages.
If you’ve had a bad experience, do warn your writer friends. And give me a heads up while you’re at it. We do want to make the indie writer experience a better one, don’t we?
In conclusion, writers are entirely responsible for their own work. They must do their due diligence. Do some research before spending your hard-earned money on editing. Caveat Emptor.