Forget the referenced study, forget his suggestions for a proper study and consider the above quote.
Most search queries are longer than one word nouns. Chitika recently pegged queries at between 4.07 and 4.81 words on average, depending on the search engine. A couple months ago, Hitwise reported that 27 percent of searches that produced clicks were one word — leaving 73 percent of searches not represented in this study.
Perhaps because we (in our industry) tend to lump all terms as 'keyword' many, especially noobs, tend to fixate on single word terms or at most one word plus an action verb. It is not so much wrong as cutting one's way through the thickest part of the forest. If there is a common behaviour resulting in thin or shallow content this might well be it.
Let the SEs do the work, they actually are quite happy to truncate. Write long copy full of rich adjectives, synonyms, even antonyms, as well as 'target' nouns; include action calls beyond those required for immediate conversion, perhaps as internal or external link text... throw up a banquet for the visitor and let the SEs put multiple query response 'selections' together.
In other words write for the purposes of yourself (business, i.e. conversion) and your human visitors (information, context, eye candy, calls to action, et al) and allow the SEs to make of it what they will - and most times they'll make much more of it than if you chase a single 'term' all about the page.