What is a minimalist argument?
For the same reason we discount rookie performances in Summer League, we also discount guys who get big stats on losing teams. But when you’re on a losing team and play great to beat a top team, that has to mean something.
Boston had the best defense in the league, and Kuzma carried the Lakers in the fourth quarter. Houston was #6 in the league, and Kuzma shredded them.
If Kuzma improves his defensive rotations and help defense, he’ll be just as good as Tatum. It’s certainly possible that Tatum could improve in the next couple of years and attain an even higher level.
But your argument that “He benefited from a lot of good easy scoring chances” applies far more to Tatum, who was given wide open shots for most of the year because so much attention was paid to Kyrie Irving’s drives.
I heard Haralabos Voulgaris note that Tatum set some historic shooting record for rookies and he doubted there was much room left for improvement. (He shot better during the regular season the Curry and Durant, and was only .004 behind Klay Thompson).