I think the trick is to have the "AR" be truly AR - such that you are augmenting the world rather than simply throwing information windows onto some kind of 2D hud. If your AR is able to texture map places and things in a way that it behaves as seamlessly as street signs or painted road surfaces already do, then you're not so much throwing *more* information at the user, but *better* information in the same places they already expect to look. Sat nav directions painted on the road surface, personalized menu options and prices on the passing McDonalds sign, improved brake lights of other vehicles, wall-hacks for oncoming cars at blind intersections, virtual billboards over top of roofs or textured onto the sides of buildings. The advertisement part is probably key though - it would basically allow for the device to turn any part of a city into a times square-like advertisement platform, albeit entirely personalized, so even if these devices are freakishly expensive they could be subsidized by ads in a way that smartphones never could. And much like modern web advertising, it would probably be self-moderating as any overly obnoxious implementation of ads would be a death knell for the device. There's a substantial amount of sensory noise in the physical world that we live in - most information that we see during the course of a day is impersonal, if not completely irrelevant to the people receiving it, so we naturally end up spending our day filtering out 99% of the things we see. Having the physical environment behave more like a personalized, selective web experience and less like the shotgun, lowest common denominator network/cable TV experience could be pretty compelling.
But until we have some reliable method of doing that kind of open environment spatial tracking, then on-the-go AR will probably not be much more than a smart watch attached to your face, a la google glass.