A Hurdle for POD
Generally, I'm not sure this matters so much if the publisher isn't targeting millions of buyers. Still, poor editing can grate, particularly if combined with poor layout design. (I stick to my own preferred template, created from trial-and-error, and follow a few basic rules: no orphans, no widows, etc.) But the cost of adding a professional editor on staff (or even hiring on a line-by-line basis) is too expensive with books that might take 5 years to reach 1,000 copies.
So, there's a potential market for alternatives here. It probably wouldn't be worth it for an editor to offer "quick edits" for a lower fee. Perhaps there is opportunity, though, for small community-oriented editing groups. Set up a sort of private wiki for 5-10 interested people with a background in writing/editing, and an interest in the subject, and give them the ability to make basic edits. Not sure how that would offer compensation, but it's one possible angle.