Lots of words... still not convinced.
The bigger match-ups argument I can buy; but the more teams you add, the less often you play everyone.
Yes, but the conference can ensure that the big boys are always scheduled. Given the line-up for conference games since Nebraska joined, the Big Ten is focused on ensuring as many high-quality matchups as possible.
This gives you diminishing returns at some point. I see no reason why those diminishing returns don't happen when you go from 12 to 14. I'm not saying they do; but the suggestion that going from 12 to 14 is good because it means bigger match-ups only holds water in the years when you actually get the match-ups you want. And what if moving to 14 means we lose the intersectional games that we've had the last few years? Then the net addition is zero.
Again, you assume that new teams are watering down the matchups. I would argue that matchups against scrubs are hurting the conference right now, and new blood featuring better perennial teams will bring in more revenue. The Big Ten essentially has 4 very good teams (OSU, Penn St., Michigan, and Nebraska), 4 mediocre teams (Wiscy, Michigan St., Iowa, and Illinois) and 4 poor teams (Minnesota, Purdue, Indiana, Northwestern). These are generalizations, but you get the point. If we add more very good teams, the frequency of good matchups increases, not decreases. Instead of getting 2-3 doormat games a year, it decreases to 1-2 thus increasing viewership.
As for your hypothetical of "locking up the state of Georgia". I'm not buying. You only lock up the TV sets that are watching GT right now, and that's not everyone in the state by a long shot and TV execs, advertisers and their customers know it. You are adding more viewers, but I'm still not convinced you're adding more viewers per game.
Thus why I said Atlanta Metro. Additionally, advertisers are going to look at that Orange Bowl game with Iowa-GT and its 26% viewership increase from the year prior and know that both teams can bring in the eyeballs when needed.
Having said all that, my mind is still open on this. There may be an argument that sways me; but I have yet to see it.
If you can't see it now, your only going to see it when BTN reports massive increases in revenues from adding more and more TV sets. Right now, there is no reason more sets are going to get added to the network. There are only two ways more are going to get added: The Big Ten is a huge draw because they are popular and beating down on everyone, or there are more teams to follow.