My own experiences don't bear this out. The entire site across the board got demoted, and cannot identify and particular pages that were singled out.
And, of course, the definition of what is 'low-quality' is dubious to me. The only possible thing I can think of is I have some pages that are a little low on the word count -- but as it's a blog they still resulted in a healthy discussion following. I don't consider that low quality - but Google apparently does.