Yeah, sounds is part of the rally experience. I think that without fuel rally will change a lot, something like what happened at middle century when it stops being an endurance sport with cars driving from Paris to Beijing and it started being what we see today. I think it will change in some other form of sport.
Maybe it will become more circuit-like but with huge laps still in the forests. Or maybe something else. I know it's like blasphemy but I can't see it being like it is now if engine will be elettric.