You're right in a lot of that. But I think he's thinking more in the area, can't hit a QB like back then and the way DB have to play the WR now.
A QBs job is a thousand times more mentally demanding today than it was even 20 years ago, but it's also a thousand times less physically punishing.
It's the reason we are seeing more QBs play at a high level at an older age all the time.
Favre was like 8,000 when he retired finally for the 44th time. But right behind him you have Manning, Brady, Brees... all going to play into their 40s. In the case of Brady, he may play into his late 40s.
I wouldn't be surprised if 50 became that new "retirement" age for QBs before long. They train harder and better, there's better science, they take fewer hits, and the hits they take are no where near as hard.
But the mental demands on them are so extreme now. The game in constantly evolving, and defenses are getting smarter, more complex, more advanced, and a QB has to know every possible alignment, stunt, blitz... it's insane.
And everyone knows it's become a QB league. A QB who's team is losing, no matter the circumstances, is the villain. He's the scapegoat.
It's harder, mentally speaking, to be a QB today, than to be the ace pitcher of the Yankees, or the goalie of the Red Wings. Everything is your fault, and no one likes you.
I've even heard fans in Green Bay bitching about Rodgers and why he's not as good as Favre. I mean... fuck.