The ecosystem is there, and getting better all the time.
Reasonable recommendations for ancillary publishing services can be found on any of the popular writer's forums like absolute write or the author's cafe on kboards. Several relevant subreddits also exist.
Like everything, there are scammers and people looking to make a quick buck for shoddy work, but there are also a LOT of frustrated former English and Art majors who have hung out a shingle.
As far as editing goes, you can pay for pretty much anything the publishing houses provided, from a proofreading to copyediting, even a developmental edit (recommendations on story structure, what works, what doesn't work, etc.).
In my experience, book design and editing are easily handled by most authors with even an iota of motivation. It's the marketing that baffles most people. Congratulations, you wrote a book, now what? etc.