This is a popular notion, but I'm not sure how well founded it actually is, since we really only have one search engine that's really been struggling with SEO s

This is a popular notion, but I'm not sure how well founded it actually is, since we really only have one search engine that's really been struggling with SEO spam, and that is a search engine that is also in an uniquely tricky bind where they're primarily an advertisement broker, and thus extremely limited in what they can do about search engine spam without hurting their own bottom line.