A good editor is worth their weight in gold. Myself, I’m a frugal person, so I do my own ferocious self editing. I once belonged to a writers group, and the material the members submitted for critique made me cringe. Their story ideas were good, but were full of unnecessary adjectives, numerous misspelled words, run on sentences, and they had their characters grunting, snorting, huffing and puffing. I would spend time editing and when I gave back the material, the people were offended. I figured these people were looking for praise and not the truth.
In return for the sacrifices you must make in order to self-publish, you will gain total control over the project. In addition, any profits from sales of the book will be yours (not just a royalty percentage as with either a traditional publisher or a vanity press), and in some cases it may be the only way of getting your book into the hands of readers. However, there is no getting around the requirement to get the tasks done one way or another.
You also said it’s not fair for self-publishing authors to apply those standards to editors when they don’t work with publishers themselves. It’s one thing for authors to have the right to publish their work and make it available for readers to judge its merits, and quite another for someone to ask those authors to invest in them for their expertise.
What an editor does is discover your characters, your situations, and your images without seeing any of the creative process that brought them to life. Where you might see all the crossings-out and labors, all the accidents and decisions, the editor sees only a page. This is the clarity you need, and you can never achieve it for your own writing, simply because you envisioned it first. The editor will tell you what an attentive, an educated, and, most importantly, a new reader will experience while reading your book.