Why is 2 Channel better than multi-channel?


I hear that the music fidelity of a multi-channel AV Receiver/Integrated amp can never match the sounds produced by a 2 channel system. Can someone clearly explain why this is so?

I'm planning to upgrade my HT system to try and achieve the best of both worlds, I currently have a 3 channel amp driving my SL, SR, C and a 2 channel amp driving my L and R.
I have a Denon 3801 acting as my pre. Is there any Pre/Proc out there that can merge both worlds with out breaking my bank? Looking for recommendations on what my next logical steps should be? Thanks in advance.
springowl
Landok...I disagree about your theory that a center speaker is good only for centered sound. The center speaker can combine with a left or right speaker to create a phantom halfway between. For example, if in a matrix multisound system the Center is driven with L+R, the L image will appear between L and C, with the same panorama of sound that can be created with stereo. Likewise for R and C. Of course if, as is often the case, the center speaker is inferior to the others results will be degraded.
Eldartford,

But why fool around with a center speaker if it has the potential of degrading the sound of a recorded material? What purpose does a center speaker provide then other than more clarity of oral discourse or dissertation that is in synch with the performers on the screen? Why would one even consider the images coming from between L and C and R with the use of a center speaker in a matrix modality? Good to excellent soundstaging of one's 2 channel system will give you all those images without muddying it.
Landok...Somewhere there is an audiophile with a monophonic system, who doesn't want to confuse his sonic image by having it come from two places :-)
velocity,

Keep the debate civil. I am not criticizing your views. I'm simply stating another perspective. I'm sure that you have the best equipment but I'm not interested in knowing that. My opinions are mine alone and I'm not really out there trying to convince you or anybody for that matter. I'd rather settle and listen to a scintillating 2 channel pure stereo sound and when I finally become inattentive, I will turn on my BRYSTON 9B SST amp, just for some diversion.
I can't comment on multichannel, but I CAN say with absolute certainty that my two channel set-up plus sub-bass unit generates SPECTACULAR imaging, which I've already described at length in my review of the Intuitive Design Summits. Depth, width, and height are all there, and in SPADES. I have no desire for a multichannel system, although I've never really listened to one, unless that's what they have in the theaters. If that's what surround sound is supposed to be like, then I think it sounds insultingly artificial. But hey, maybe someone with a "better system" than mine can "bring...(me) up to speed."