The purpose of my post you responded to was comparing mainstream media news to alternative media. You are helping make my point. Our generation watched the debate live. There were 13 million of us. If you couldn't watch the debate live, there is limited access to watching that debate now. Younger people today don't watch things live. They watch it on their own time. What percent of the 250 million watched the entire video, we don't know. Obviously way less than 250 million, but it is still a substantial number. Main stream media in it's current format is dying.
I understand and agree with your analysis. The problem is there is no other metric to make comparisons. It could be argued the 80 million views of the interview verses the 13 million views of the debate taken when the debate ended is a fairly decent head to head comparison. This is before the video went into peoples Twitter timelines, etc.
For those that want to make this post about Republican politics instead of media. A better head to head debate comparison is the August 2015 Republican primary debate that included Trump, had a viewership of 24 million compared to the 13 million this week. 45% fewer Republican's have any interest in the current crop of Republican candidates. This number is very telling.
https://money.cnn.com/2015/08/07/media/gop-debate-fox-news-ratings/index.html