I'm only 1/2 way through this but it seems to be a practical assessment of the impact of television on North American (and perhaps general) politics over the past 40 years. In other words, from the 3-network era of politics that began its dominance with the Kennedy Nixon debate, and started to move into Cable news... to the 'single channel single viewer' landscape of today.
https://fivethirtyeight.com/features/politics-podcast-how-tvs-evolution-explains-todays-politics/Startling to me that it fully subsumes McLuhan theory without feeling at all eccentric or overly academic.