I can't really fathom why publishers aren't moving faster with ebooks. A couple articles I read (one from Tor's Patrick Hayden) mentioned it is partly a time management thing. They have thousands of backlist, they have new books, they have all the same chores--and ebook is an additional one. And of course it isn't as though they have new staffing.
And yes, I'd agree that editing is probably one of their most valuable functions. Their "branding" and marketing don't hurt any either.
Maria
Sage: (multiple formats; Amazon or Smashwords--$1.00)
Catch an Honest Thief (Kindle only format: $1.99; a cozy mystery)