A recumbent isn't "superior" to a traditional frame. It has select improvements, but for the general consumer the ride quality of a traditional frame is much better.
For bumpy roads, you can always stand on the pedals on an upright bicycle and use your legs as shock absorbers. You can't really do that on a recumbent.
But the general consumer most likely doesn't want to spend too much money on a bicycle and recumbents tend to be a bit more expensive compared to uprights.