There are some talentless published writers because often times its not what you know, but who you know. Think of how many celebrities get their crappy books published because, bottom line, their name will sell the books. I'm sure it happens often too that someone (non-celeb) knows someone (publisher/agent), and they get their crappy novel published because of their connections. It happens in every industry, too, and in most companies. It sucks because its unfair, but that's what's real.
yes, of course that happens... such as way back when harry truman's daughter wanted to be a novelist and more recently with such putative celebs as sharon osbourne and model katie price... but you'll notice that despite their books' gaining a place on bestseller lists due to their name alone, their writing [if it is their own!] seldom if ever earns the respect of literary critics...