Anyone wishing to pay someone 500 bucks to read their book just so they can be given a short and unhelpful overview is arguably getting what they paid for. Naturally, self publishers and the like can’t really justify the amount they’d have to spend on a real editor of story structure, but it still baffles me that these so called developmental editors exist. That is, unless they have a follow up service after the fact that is actually worth it.
I'd suggest working through each change so you can learn for next time, rather than just clicking Accept All on the Track Changes version. This will take time, but it's well worth it. I usually accept 80-90% of my editor's changes and the manuscript is improved considerably by the experience. After the line edits are updated, I send the manuscript to a proofreader for the final check before publication.
BookBaby’s Book Editing Services offer three different options for authors: Line Editing, Copy Editing, and Proofreading. These different levels of editing services cover everything from basic grammar and misspelling corrections to review of the story narrative, story development, characterization, and sentence structure. We offer options to ensure that each author is satisfied with their editing service.
Attention to detail is a critical skill for editors. So how do you screen out editors who might not wield a virtual red pen with the chops to catch every typo, grammar problem, style issue, and the like? You could post a job ad for an editor and subtly screen out applicants that aren’t as detail-oriented by including some fine print in the description.
I cannot speak for all editors, of course, but I know I and many of us would be open to editing just part of your book at first, say, a particular chapter or two that you sense needs a lot of work. That is often enough to show you mechanical errors that you tend to make repeatedly. You can then go through the entire manuscript yourself looking for as many of the same kind of errors as possible. You will sharpen your basic writing skills in the process, and it will pay off in all future projects.