Most of the civilians don't buy these guys -- they are the sports cars, and generally they are no use to the normal population for most tasks. A pistol is a better home defense weapon alongside a shotgun (due to the spray and low penetration through walls... ), and for hunting generally no animal is going to take 3-4 rounds to kill, so burst weapons aren't useful... Generally, squeezing each shot is good enough...
I am aware of a shotgun though that shots double barrels off "each rack" and is fed via two magazines... This could put more lead out than an AR in most uses.