I did not downvote, but just wanted to mention that the first two do not require a traditional publisher. In fact none of them do, but especially not the first two.

It is true that there are real quality issues with a lot of self-published work because you don't _need_ an editor to publish your book. Heck, you don't even need to do a self-edit pass. Write it and hit publish! But it is increasingly an expectation that you have one, because quality expectations are extremely high, especially for competitive money-making genres.

I started out self-editing and now pay for three professional edits for each release: developmental, copy, and proofread. Professional editors are not exclusive to traditional publishing houses.