and it will probably never change. "Better," or even "favorite," can mean all kinds of things, but I can't imagine a movie becoming more canonical to me. John Ford, and especially his westerns, were a gateway for me to develop a real interest in films. And they're rich enough to endure as favorites after I "saw move movies." And westerns in general are my favorite genre. No movie has everything, or even does everything that such and such genre/director/ect. could do, it's impossible. But I don't think that either the director or the genre ever had or really could have achieved a greater scope in one movie without becoming strained or contrived in a way that would ruin it. To my tastes it's just definitive in alpha-and-omega sort of way.
And I just enjoy the hell out of it, every time I see it.