I remember educating you on the use of TS% in the past, and how perimeter players and post players generally do not compare. It's like comparing rebounds, assists, blocks or FG% between players. What is considered good for a perimeter player could be considered horrible for an inside player for one category, and vice versa for another.
The reason is due to the use of 3 point shots + FTs and how TS% favours perimeter players.
For example, a player like Monta Ellis, who is known to be a player with questionable shot selection, has a career TS% of 52.6% (similar or better than 3 of the 4 Kobe series you cited), and the reason lies in how he's a 31.8% 3PT shooter in his career out of 2.8 attempts (17% of his total shots). This 31.8% shooting essentially translates to a 47.7% true shooting (a respectable number for a perimeter player if it was actually FG%, and higher than his career 45.6% FG%). Add to that his .773 FT%, and how 18.5% of his total career points came off of FTs, it helped dragged his TS% to Kobe best finals numbers.
Compare this to, say, Chris Webber, who, in general terms, is a relatively decent inside player his entire career. Webber had a career TS % of 51.3%, which isn't bad for a post player, but most definitely a full % lower than Monta Ellis. Is Webber a less efficient player than Ellis? Of course not, what kind of idiot would say that other than those who have absolutely no idea of statistics and how they work?
Another reason is because Kobe won 5 championships while Duncan "only" 4. In your comparison, Kobe's worse series (2003) was thrown out, while Duncan's wasn't. We also haven't looked at losses (2004, 2008 and 2013), and dismissing the losses and only included the wins is a highly questionable comparison.
Finally, the roles of Duncan and Kobe were different. Kobe was the clear cut sidekick in 01 and 02, and had a dominant front line (Kobe's equal of better) to take pressure off him in 09 and 10, while Duncan carried the Spurs offense in 99 and 03, had an equal/sidekick on offense in 05 while being guarded by arguably one of the best defensive frontcourt ever in 05, and was a clear defensive anchor in 07. Kobe was never thrusted in an offensive role in a Finals series like Duncan held in 03 or even 99, nor had he ever had the level of defensive attention that Duncan had, ever. I can play against a bunch of kindergarten kids and have a TS% of 150%, but that won't make me a more efficient player than Kobe Bryant.