Ultimately, it is all about the money, but regardless, he recognizes that if the NFL doesn't become a safer league, the league will lose money due to lawsuits. Its not about 18 games. Regardless of motivations, he is trying to make the leave safer, thus why the emphasis on punishments for safety related issues.
If lawsuits were the overriding issue, why would he still be pushing for 18 games?
The owners recognize they need the players to sign off on 18 games in order to do it. But the players are hesitant because of injury concerns. So then, the equation becomes simple. If the game is too violent for an 18 game schedule, you make the game less violent. You come down hard on stuff like Bounty Gate. You fine players out the wazoo if they hit anybody on the head. You basically eliminate the kickoff return from the game.
Then, when it's time to negotiate again, you can say, "look, haven't we addressed these concerns? Haven't we been vigilant on the safety issues?" Blah blah blah. Anything to get two extra games the fans have been clear in poll after poll that they don't want but the owners view as a huge pile of basically free money.
But it's not about player safety. At the end of the day they might reduce the chances per snap a player might get injured (in some ways, but not in others). But the two extra games will just increase the total number of snaps to compensate.
Like you said, it's all about money. I just hate that Goodell is called the Commissioner when he only represents the owners in these matters.