I understand your point, but LeBron was ordained before he won anything, no?
In fact, one could argue that the preordaining of LeBron is a bigger factor in his championships than his actual skill set. In other words the NBA made LeBron's championships happen. If the NBA had needed Barkley to win, he would have won.
I assume by your statement you are one of those conspiracy types who are convinced sports leagues do anything they can to promote certain stars over others.
In Barkley's case, he and that Suns team were massively popular and it wouldn't have hurt the league at all if he had won the title that season. To use a purely orchestrated event as an analogy, in wrestling the "faces" win sometimes too, to send the audience home happy.
Additionally, the Lakers and Celtics dominated the 80s and nobody complained that the league would be better if only one team were dominant. In fact people probably love that decade of basketball more than the 90s.
If LeBron was being protected, why would he be allowed to lose two titles? Especially his second Finals appearance when the opposing team was the Mavericks, with the rebellious Cuban as an owner and the lack of any popular stars (Nowitzki is great, but no kids are buying his sneakers)?