I would suggest logistics on that one - it's a pretty reasonable exercise in engineering to put seven 100W amp channels and a power supply in a single chassis. When you try to add a pre-amp section, digital processing, DACs, video switching, a tuner, and the space-consuming spread of inputs and outputs on the rear panel, you are going to be trying to use a lot more space. Perfect case in point - there have been many, many complaints about the size of the 990's chassis, and that very significant chassis is as big as it is because the design developed by Sherwood allowed for either a processor or a receiver with a 120Wx7 amp section.