This article argues that TV now-a-days is more cognitively demanding than it has been in the past. For example there's many shows that have multiple plot threads and that are more willing to use actual accurate technical jargon rather than just techno babble intermixed with occassional bits of plot information that actually matters.
Moreover, even junk TV is more sophisticate. Reality TV often involves strategies and changing rules that make for more interesting conversation than the newlywed game or the like.
This article is fascinating both for its thesis and because it elucidates the nature of cognitively demanding media. Interestingly video games are cited as contributing to this phenomon.