Another data point: id was killing it (and, to us, Carmack remains undisputed). But they completely lost out the next generation, to Unreal, because of vehicles. I don't think that'll happen here, just disclaimin' past performance is no guarantee of future success.
Though, to be fair, the Quake engine underlied Call of Duty, the most successful franchise (I believe), and it really showed in the framerate. Note: no vehicles. And yes, past tense.