I think you're overestimating how much power Kobe has in this situation.
This is bigger than just Stern vs. Fish; the lockout is about the owners and the players.
As
NBPA president, Fisher represents the 430 NBA players.
As a player, Kobe only has the authority to represent himself.
With a CBA, it's a complex piece of negotiation with profound, long-lasting effects for the entire league.
The sticking points that are keeping the players and the owners from reaching a new agreement are ones that Kobe is neither entitled nor qualified to negotiate.
It's just not as simple as saying "Kobe could end the lockout".
By all accounts, Kobe is a single-minded basketball playing machine who works as much on his game as anyone else in the league.
This is what makes him a great player.
What he isn't is a leader and speaker for the hundreds of NBA players whose livelihood is at stake here.
Fisher, as the president of the NBPA, is all of the above and by all accounts is exactly the right person for the job:
Fisher has worked hard to extend the reach of his office, and union insiders say that no player leader has had a better, more nuanced grasp of the CBA or been better able to articulate a vision for the union.
I recommend taking a look at the article quoted above if you want to know what exactly is at stake here.
Any meaningful discussion of the lockout requires everyone to be informed.
Besides, it's unfair to just pick on Kobe for this.
By singling him out, you're basically discounting all the other star players in the league.