Imo the problem mainly lies in Google's square. All SEO tools exist for the reason of it being possible to game search results in the first place. It's inevitable that companies will offer tools and services to do so when there's such a huge market for it.
Google has gotten better at discerning between crap and quality content, but they still have a long way to go, and I'm unsure if it can be fully fixed the way search engines currently work.