If you are going to bring in speaker power requirements into perspective, then you need to look at what cross over point you are planning to run the speakers at.
Set them at 100hz you will need significantly less power of the receiver than if you try to run them at 40-50hz.
But I have also questioned why a pre amp costs the amount that it does. There must be other parts savings inside the units that bring the cost of a receiver down other than supply and demand quantity adjustments.
I have a Yamaha CX-A5000 Pre-Pro that I bought last year(very impressive). The unit itself cost more than Yamaha's top of the line AVR. There are some extra features along with a balanced power supply and outputs, yet does it sound better than the AVR? Other than having separate power amps to plug in to with more power, honestly, I am not really sure. At 30 lbs. it is heavier than a lot of AVRs yet, I suppose because so few companies actually manufacture them anymore, I guess they figure they are sold to audiophiles who insist on separates and are willing to pay extra.
This was the first separate that Yamaha has introduced in years but I am told it did very well since along with the their newly introduced line of AVRs, they are going to introduce a successor in the fall with all the latest features(HDMI 2.2, DTS-X, Dolby Atmos etc. etc.).
