Hip Hop/Rap isn't dead though, there are several venues to discuss,acquire and in general be "Hip Hop" over the internet.
There is a large Hip Hop community that promotes and listens to a wide variety of acts.
Without the internet I'd say the statement were true but that isn't the case if you ask me.
R&B on the other hand isn't built around a culture like Hip Hop.
There is no independent R&B circuit like there is for Hip Hop or Rock.
You can't go to a one stop shop for R&B like Datpiff or HotNewMixTapes (both of which actually have a small R&B presence).
R&B is essentially urban pop music, it's been blending with Hip Hop for years now, well over 15 of them I'd say.