This will be debated all season, and beyond.
You really think so?
Tatum missed 5 games, Boston went 2-3 despite getting Walker back for the last 4. They were 7-3 with Tatum to start the year and without Walker playing at all (and when they close out the Bulls will be 8-3 with Tatum and no Walker). And despite the Cleveland game yesterday, Boston is still 3.4 points per 100 possessions better when Brown is on the bench.
Tatum is the most valuable Celtic because he is the best Celtic and frankly I don't think it is all that close.
Genuinely cannot believe you're clinging so desperately to the laughable idea that we're a better team with Brown on the bench by using raw on/off. Funny stuff
And yet historically that stat has been a pretty darn accurate predictor of actual importance to winning. Look at champions. The Warriors, for example, Curry, not Durant, is what made them tick. Durant was a better player than Curry, but he wasn't more critical to the Warriors success. That was Curry. Without Curry the Warriors were a good team, with Curry the Warriors were an all time great team and that wasn't the case for Durant. We saw this quite well during the 17-18 season when the Warriors were 41-10 in Curry's 51 games and 17-14 in the 31 games he missed. They were 49-19 with Durant so 9-5 without him (there was some overlap in missed games). Curry's on/off differential was +12.1. Durant was +1.9. And that was fairly consistent all 3 of their seasons together. Curry made the Warriors go even though Durant was the better player. You see it doesn't necessarily equate to skill, talent, etc., merely how integral the player is to the team.
Tatum is far more integral to the success of Boston than Brown is. We've seen this pretty consistently over the last 3 years in that Boston just isn't very good in games Tatum has missed and plays about the same (or better) when Brown is out. It doesn't mean Brown isn't a good player, he absolutely is, but his value to the scoreboard just isn't very high and the reality is, Boston has just been better with him on the bench over the last 2+ seasons, while Tatum has been by far the leader in that category. The fact that they both start and have played similar minutes makes that way more striking as you generally find units to have fairly similar numbers, especially when the individual production has been similar enough. Boston needs Tatum, Boston doesn't need Brown.
What is it in Tatum's game that I'm missing that makes him that great, if we're following your reasoning?
These on/off numbers suggest that Tatum is basically as important as what LeBron James is to the Lakers.
Anthony Davis is a great player, but according (and also to the eye test to be honest) to the numbers the Lakers are only functioning at top level because of LeBron. Same with Harden in Houston in comparison with any other star that played there (Paul, Westbrook).
To me Jayson Tatum looks like 15-20 as a player ranking in the NBA and Jaylen Brown like 25-30. How come this isn't reflected in the numbers?
And will the improvement of Jaylen Brown change this difference between Tatum and Brown?
You're missing the fact that raw on/off numbers are incredibly noisy. Tatum isn't doing that well in adjusted plus-minus metrics.
Except you know you can actually see Boston's record in games when Tatum is out and games when Brown is out. I've put that in this thread plenty of times but it bears repeating again.
Boston's record without Brown available / with Brown
17-18 season - 8-4 / 47-23
18-19 season - 8-0 / 41-33
19-20 season - 10-5 / 38-19
20-21 season - 0-0 / 10-6
So 26-9 without Brown or 74.3% and 136-81 with Brown or 62.7%
Tatum has been far healthier so more room for variance here and there, but here are his splits
17-18 season - 2-0 / 53-27 (Tatum's rookie year)
18-19 season - 1-2 / 48-31
19-20 season - 2-4 / 46-20
20-21 season - 2-3 / 8-3
So 7-9 without Tatum or 43.8% and 155-81 with Tatum or 65.7%
You can call the stat noisy all you want, but the only place any of this matters is the actual wins and losses and in that, Tatum is way more important than Brown. It isn't close and it hasn't been close since basically Tatum stepped foot on the floor. And over the approximate half a season Brown has missed in the last 4 years, Boston actually wins those games at a much higher percentage than in the games Brown actually plays in. That quite simply is a fact. Boston wins more when Brown doesn't play. Period.