Hmm so the Nexus S isn't a flagship device I guess even though it is the only 4g Nexus S out there.
Sprint really only puts out one "flagship" phone a year (Instinct, Pre, Evo 4g and now 3D in the most recent history) that they really put all of the marketing money toward.
That isn't to say that the Nexus S 4G (or the Hero 2 years ago and the Epic last year) weren't top tier devices, they just didn't get the push that the "flagship" phones did.
You can still see that in the fact that most everywhere (at least in KC) the EVO 4G is on billboards, the main signage in the stores and most of the ads I see on TV that aren't simply Dan talking, always have the 4G in them