Google's algorithm is layered and weighted. And although an argument can be made on behalf of other "human" factors such as manual reviews, CTR, page views, etc. etc. (contentious points), The rest of the algo is largely math. Having the right words, in the right densities, in the right context, etc. WILL make the difference (all other things being equal). Sometimes content optimization isn't the underlying issue. Links, link velocity, relevancy, on-page site performance factors, internal link structure, and so on, play just as big of a role.