"The trendline in pro sports seems to be to increase the number of games and to escalate player salaries as TV revenue skyrockets."
That doesn't seem to be true.
The NHL has been at 82 games since the 1995-1996 season.
The NFL has been at 16 games since 1978.
The NBA has played 82 games since the 1967-1968 season (and there is some consideration being given to shortening the season. [
www.nba.com])
Major League Baseball has had a 162 game schedule since 1961.
Personally, I don't see a trend towards increasing the number of regular season games in pro sports.
What I have seen, however, is expansion of the playoffs: the NFL (2002), NBA (2003), Baseball (2012) all added teams and/or games to their playoffs way more recently than they added games to their regular season.
IMO the NFL is more likely to add 2 more wild cards than go to an 18 game season. Not only would those 2 additional games generate additional income for the NFL you are likely to see increased viewership towards the end of the season due to more teams having a shot at making the playoffs.
AlbaNY_Ram