In my view, what ruined the NFL was the domination of the game by wagering. It is well-known that wagering on games being televised is 60 times higher than on games not shown on TV, simply because it is more difficult to rig a game when there are so many witnesses. With the advent of cable television and the proliferation of channels, more games were broadcast, and the wagering increased, but the odds were less certain. The "instant replay" rule was introduced to enable a veto of referees' calls on the field, by judges in the press box with multiple cameras available to them. I began to see games being pretty obviously manipulated, although not in terms of their outcome, but rather in terms of point spread, quarter by quarter, as well at the end. So, we began to see a lot of dramatic misdirection, like scantily-clad cheerleaders, player histrionics, and a marked increase in the level of violence. It became a contest between compulsive gamblers trying to outsmart the fix, and fixers baiting the gamblers.
The last game I recall watching was in September, 1988. Cleveland was at Cincinnati. The Bengals were killing them in the first quarter. When the Browns got the ball, the Cincinnati defense simply backed up, and let them score. Why did this happen? Because with such a one-sided contest, the network would pull the plug on the coverage, and switch to another contest. Consequently, wagering on the Browns-Bengals game would dry up, inhibited by the absence of TV coverage. So, wagering trumps bloodlust. Las Vegas trumps Hollywood.
It's sad, it used to be a good game.
I have many avatars, lol. I am sure by next week it will be a different one, heh.