There is a notion that the NBA has become a soft league with players who are not used to play against hard nose defenses often related to the '80s and '90s. Even though it's true a lot of things that were a normal thing back in the day like hand checking and a hard foul that would go without a serious consequence from the refs, NBA has evolved quite a bit and players nowadays are in many ways more skilled than players 20,30 years ago.
Kobe Bryant who is regarded as one of the best scorers in NBA history and a true basketball geek who often studied other players' moves believes the rules in the '80s would benefit him more. He said pure scorers like Carmelo, KD and himself would be even more productive because defenses were played straight up and there wasn't so much double-teaming.
"But for scorers like myself and Carmelo and KD, the rules from the '80s can be more beneficial for us, because you have to be played straight up. You want to double team, you got to come all the way over. So, for us, I don't care if you hand check us with three hands. If there's nobody behind you, you're not going to stop us. So the zone I think cripples some of the top scorers.”
It's hard to tell how many points would guys like KD, Kobe and Carmelo score on a nightly basis against the players 20,30 years ago but they would definitely be successful because their talent is one of a kind. Kobe's reasoning about hand-checking makes sense because they are used to play that way during practices so this is not something new to them.