If it was about money I would agree with you. But it doesn't look like that's the case. The players get around 47% of all league revenue so if an 18 game season generated an additional $2.5B then the players would get $1.175B of that. It seems that if it was a question of money that more than a billion dollars a year every year would do it.
Here's what the real deal is:
"The players’ union estimates a longer season would result in a windfall of new money for the league — up to $2.5 billion per year, according to the Journal, of which players would receive half — but would hurt players’ longevity. That’s crucial, according to NFLPA estimates, because the average NFL career is 3.4 years but would drop to 2.8 years with two more games each season. The minimum required service time for players to receive a pension and long-term health benefits is three years." [
www.washingtonpost.com]
AlbaNY_Ram