iPhone 4 runs iOS 6 just fine--it doesn't really matter what version of iOS was around when then phone was released.
That said, chances are it's wording that was left over from tips/promotional information related to the maps app prior to iOS 6 and when Apple was updating it for iOS 6 they might have overlooked some small parts, like a couple of words referring to street view (which was there with pre-iOS 6 maps app based on Google Maps).
At the same time, that is also not to say that Apple won't roll something out (with time likely) that would be similar to street view that Google has for their maps.