The game survived that, I'm sure it can survive a few more 6 agains. That's what the game does, it evolves.
I'm with you on the survival but I'd question if it really evolves. As you point out the change rarely acheives what it set out to but we trundle on.
'Cause the secret is, it's not about the game. Really it's having a media product which is deeply relevant to a large group of people. Changing the rules, so long as there's still enough genuine competition and irrational tribalism does very little either way.
It sucks for the rusted on fans but we'll lump it because well we're rusted on fans.
But it's also largely wasted effort.
If I think about it we've changed virtually every aspect of the game in my adult life everything other than passing backwards,the field dimensions and # of players (the last two would actually create more lasting impact but have infrastructure and attachment hurdles)
Take just the tackle for instance we've changed how you can use your upper body, how you can use your legs, how you can attack their legs, how the tackled player uses their upper body, how a tackled player submits, where tackle impact needs to finish, if you can take the ball in the tackle, what tackle # it is, what the tackler can do to the tackled player on the ground, how the tackled player can get up, how much room the tackled needs to give them, how the play of the ball works, where you play the ball.
And in all that lost time to injuries have increased and the distribution of the comp follows similar patterns.
That's not evolution IMO that's just throwing stuff at a wall every year so management can say they've changed something.