Well that’s a dishonest comparison to compare modern players who have high tech, high knowledge, modern training and supplements etc… to bygone eras.
If todays players played back then, they wouldn’t be the players they are now, because all they did was in-season practice, drills, and possibly minimal scouting. No year around focus, No health regimen, No supplements, no plyometrics and detailed weight lifting, the most basic plays with minimal passing theory explored, very simplistic schemes.
Meanwhile, if Bart Starr had access to what players have today, he’d more than likely excel and be an all star, HOF player.
You have to do that.. otherwise it’s just a dumb comparison. It’s like comparing how good of a warrior a Roman gladiator with a sword is to a US Navy seal with a high tech rifle, and crapping all over the gladiator because he got shot and died “easily”. Take the rifle from the Navy Seal, along with modern fighting techniques, health knowledge, and let’s compare them equally. Or, train the gladiator in modern combat skills, give him a rifle and health regimen and weight lifting schedule