I know, fans usually tend to analyze every single detail in his movies and find a hidden meaning in pretty much everything - while most of these details don't have one. In some interview, concerning rabbits in the "Inland Empire" (there's been a discussion about their meaning also, people even tried to explain"Rabbits" through IE), Lynch said he just liked them there and meant nothing specific. I think it can be applied to some TP things too. They create an atmosphere, that's all. C'mon, even "Cinderella" can be analyzed using Jung and Freud, but that doesn't mean it really is that deep.
Bob being real, and not a representation, is a simpliest variant, and it fits. If we remove him as a corporeal, we get a big hole in the plot.
And the slogan can be interpreted in various ways.
