I think the point was that Google spend a lot of effort to identify quality content vs. link farms, auto-generated content and low quality adsense-optimized content.

yes, but PageRank is a specific term with a specific meaning. It is a rank based on the number and quality of links to your site.

To say that PageRank will increase because the content is good quality is wrong, and I was just pointing that out.

What he meant to say was "... the search engine rankings of his site would go up..."

You're right, I misspoke when I said PageRank. The gist was the some though: higher quality content -> better search rankings (either through links due to higher quality content or google's non-PageRank algorithms).