Those are all well and good, and though I disagree with some of your points slightly, I still see what you're saying overall.
However, I'm not talking about Kevin's ability or talent-level or his upside. I'm talking about his attitude. He is a second-fiddle, "take what may come" type of guy. And I don't say that because he has the same numbers as Peja and Peja was that type of guy.
I say that for several reasons, the most compelling of all being that his teammate feels the same way.
I'm not saying that Kevin needs to be a ball hog or an over-aggressive Michael Jordan/Kobe Bryant type. There are only a couple of players that can pull that off, and he's not that good. But you have guys like John Stockton, Steve Nash, Tim Duncan, Mike Bibby, even guys like Michael Finley, Manu Ginobili, Ray Allen, etc., who put their mark on every game they play in. They don't have to dominate the ball or alienate their teammates. They don't have to scream "give me the damn ball" at the top of their lungs. They don't even have to score. But they impact the game, and even when they are having a bad shooting night, they don't disappear.
Kevin is the type of player that can be completely erased from a game, especially if he's not scoring. Peja was the same way. Some players develop an edge after a few seasons in the League, but most of the really good ones have it in them already. It can't be taught or practiced. It's not a skill; it's a quality.
And it's not meant to be a knock against Kevin. It's just that I disagree with the assertion that he's a "franchise-level" player, and that's the main reason why, not to mention the fact that he's still a one-dimensional contributor at this point. I just don't anticipate Kevin magically developing into a top level dominator. That's not the way it works.