That’s the key, it’s different. More physical and less rule enforcement that helps the offense, like today.
Many would say that’s a touger defensive era, including past players.
Pace and possessions being less back then is, at least partially, a direct result of this defensive difference.
Less rule enforcement definitely made 90s more physical
But that doesn't mean that players were better defenders back then. It's two separate issues.
Offensive skill is incredibly higher nowadays than it was back then. More outside shooting is also going to increase the pace of a game drastically.
The notion that LeBron wouldn't be great in past eras is pretty ridiculous. He was an athletic, physical freak.
You could argue LeBron has been able to play longer more in this era, but in reality a result of LeBron's tremendous work ethic and life habits.
He takes way better care of himself than MJ did