My first sale was pretty unusual in that it was bought by the very first editor who requested it. However, the book had already been turned down by about 20 agents before I tried to sell it myself. I'd also had at least that many rejections on a previous manuscript.
Publishers always take a financial risk on any new, unknown author. However, they try to hedge their bets by being very selective. Genre fiction is usually a little less risky because most of the time there is a built-in audience of readers.
I had a very few minor edits to do on my first sale, and I think that is pretty typical. Unless an author is well-known with an established following of readers, there's no reason for an editor to take on a problematic manuscript. Not when they have literally hundreds more to chose from.