Do you honestly think the Spurs don't have top-tier talent?

They do. They have 3.
But those 3 are not superstars. Unless you think that Ginobli, Duncan (of right now) and Parker is in the level of LeBron James, Kobe Bryant, Carmelo Anthony, Dywane Wade, Chris Paul, Derrick Rose, Kevin Durant, and Dwight Howard.
Tony Parker is without question a "superstar." He was a very good choice for MVP this year.
You are subjectively defining what a "superstar is," and my guess is your criteria is based on how many sneaker or Gatorade commercials these guys have.
I also think it is ironic that you suggest teams require a "superstar" to win, but of the 8 players you list only 2 have NBA championships, and all but one of them belong to Kobe.
And I don't care how old Tim Duncan is. If he is not a "superstart," no one is.