I see the movie as split into two parts. The stuff with the tire, and the stuff about the tire (the smug/meta stuff). I will grant you that if you only count the parts with the tire, you would see a fairly straight-forward monster movie. And monster is the right word here. The tire is a monster. He just is the way he is. He doesn't understand himself or his world. He's just exploring the world and doing what he wants. No reason.
The meta stuff is what pushes this movie into interesting territory. To me, the meta stuff points to the central reason that the filmmakers chose to make this movie, and why they chose a ridiculous killer tire as the protagonist. Here, the message I get is "Isn't a killer tire enough?"
An important thing to state is that this movie is not lazy. If it were just a midnight cult film for horror festivals, all it needs is a killer tire and decent sound/camera work. It goes well beyond trying to satisfy that. To me, it's the writer/director struggling with high-concept, genre and audience expectations.