How Do Some Books Get Published?

Throughout my years as a reviewer, I've often asked myself how some really flawed books get published while some really good ones are left to die on the wayside.  I've read friends' novels and novels entered in large and small contests that easily outstrip books that commercial publishers have rejected.

Take Brainy and the Beast by J. M. Cartwright, for example.  Where was the editor for this book?  Let's pretend that someone at Loose ID saw something he/she liked about the book.  Didn't he/she also see the flaws and want to make the book better?  Or, God forbid, is this the edited version of the manuscript and it was much worse before it was revised?

None of the answers will tell me what I ultimately want, however.  How do these books get published?