I think the film supports this claim. There are limits to simulated reality. Truman has grown up on Seahaven Island and despite the fact that every single person around him is a hired actor, his reactions to his world are completely real. Therefore, "The Truman Show" blurs the lines between reality and fiction, which, according to its creator, Christof, is why it is so compelling. The problem is that as Truman starts to explore his natural human instincts and desires, the show must try to keep up with him. It is much easier for Christof to exercise this kind of emotional power when Truman is young and impressionable, but as he nears 30, he knows that there are answers beyond what he sees in front of him. Therefore, the simulation starts to fail, because ultimately - there is a limit to the fakery (the wall of the dome).