I am not saying you have to see it my way, but I am just failing to understand your logic. Which year(s) was/were Kobe's peak? I can stack any years with Duncan from 2001 to 2004, and Duncan wins by a relatively wide margin in any of them.
Other than usage rate, Kobe never led the league in ANY advanced stats, and that is just embarrassing. None of the other players in the conversation for top 10 all time did not lead the league in advanced stats in any years, and often in multiple categories over multiple years. He only led the league in playoff WS in 2001, and it's only because he played more minutes than Shaq.
Jordan - WS, DWS, VORP, OBPM, BPM, basically you name it, he has it. Same for Lebron
Magic - BPM, VORP, WS/48, OWS, AST%
Bird - OWS, DWS, WS, WS/48, BPM, VORP, PER
Duncan - Drtg, OWS, DWS, WS, BPM, VORP
Hakeem - Drtg, BLK%, DREB%, DBPM
Moses - All kinds of rebounding metrics, OWS, WS, WS/48
Shaq - PER, OWS, DWS, WS, WS48, BPM, VORP
Kareem - Pretty much everything other than DBPM
Dirk - OWS, WS, WS48
Garnett - WS, DRTG, WS48, BPM, VORP, PER
Big O - WS, OWS, AST% (didn't have a lot of the metrics back then)
Wilt - PER, WS, OWS, DWS, WS48 (didn't have a lot of the metrics back then)
Russell - DWS (didn't have a lot of the metrics back then)
West - OWS, WS, WS48(didn't have a lot of the metrics back then)
Dr. J - WS, WS48, BPM, VORP (and I ignored his ABA ones)
Admiral - WS, WS48, DWS, OWS, BLK%, PER, OBPM, DBPM, BPM, VORP (pretty much everything)
Sir Charles - TS%, ORB%, OBPM, BPM
Pedo - OWS, WS, OBPM, BPM, VORP
The only player who never led the league in anything, but is in the top 20 ever conversation was Isiah Thomas.
The ONLY players in the top 20 in career WS in NBA and ABA combined league history who didn't lead the league in any significant advanced stat were Reggie Miller and Kobe, and even Miller led the league in TS%, ORTG!
Kobe had unquestionably the worst peak of anyone in the top 10 conversation, possibly in the top 15 or even top 20 conversation.