That's probably R8's biggest issue. Gamers around my age and younger probably won't stick to it for very long as they won't "get it" within the first 10 minutes of playing (or find it too hard) and will quickly move on to something else. Patience is rare these days unfortunately.
Another reason could be the "lack of content". My best bet for R8 is to regularly release new tracks/new game modes and stuff like that over time, and host their own official tournaments.
They should definitely focus on the online aspect of this game, as I think this would determine if it will be a success or not. In its current state you have to be near the people your connecting to or else it becomes unplayable.