I hate that I've almost missed out on a good KG vs. Duncan debate. Like Big Ticket, I can't count how many I've been in over the years. Before I go back and respond to individual posts, I'd like to say this: KG and Duncan have almost identical traditional stats over their careers. They've also had very similar advanced stats, though KG seems to have a slight advantage in most of these over the time period where they've both been in the NBA. So most of the pro-Duncan arguments I've seen through the years weren't about Duncan having a stats advantage, because it's just not there.
Instead, the most common pro-Duncan argument pre-2004 was that KG couldn't win for some intangible reason. He was a great individual player, but he didn't have Duncan's impact because his teams never got out of the first round. The KG counterargument was simple: Duncan had (to that point) played his entire career with David Robinson, and that if you gave KG even a REASONABLE amount of support he could lead a contender too.
And in '04, it happened. The Wolves added 67 years of Cassell and Sprewell (neither of whom were All Stars at the time, by the way) to a team of castoffs in '04: the centers were castaways Erv Johnson, Mark Madsen and Olowokandi while two of the rotation wings (Hassell and Hoiberg) had been cut by the lottery-bound Bulls that summer and the only healthy back-up PGs were 3rd string NBDL types. And with just that little bit of help, the Wolves became contenders. We'll never know what might have happened had Cassell never gotten hurt ...but at the very least that team was a contender.
So then, the pro-Duncan argument changed...it became "yeah, but KG isn't wired to lead a team to a title". And then last year happened, and the argument changed again to "Duncan is just better, and it's self evident". But the thing is, the KG counter-argument has rang true each time. Namely, every time that KG has been on a team with talent even remotely similar to what Duncan has had his whole career, KG's team results have looked an awful lot like Duncan's.
Like Duncan, KG has been a model of consistency through the years. Unlike Duncan, KG has only been on 2.5 teams with reasonable support. On those 2.5 teams KG has led a team to the WCF before all of the PGs got hurt and he literally had to be a 7-foot PG, celebrated one championship, and is currently right in the thick of championship contention a 3rd time.
Even if we ignore all of the stats and everything else that says they are similar caliber players, the fact that the same "give KG Duncan-level help and he'll win" argument that was made in '02 can still be reasonably made now and has actually been strengthened by history suggests to me that the argument has merit. I just don't see how you can divorce teammate caliber and simply say "Duncan's on another level, period." Doesn't make sense to me.