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
Can't say which sounds better, depends on the recording I guess. I don't have a whole lot of multichannel recordings yet, but of the ones I do have, some are much better in multichannel and some are much better as two channel in my system. I think my opinion may be a wait and see type of thing. I know some people like old mono albums and say they should never be mixed to stereo, could be the same thing with two channel recordings. Rock music such as: Beck, Frankie goes to Hlooywood, Mike Oldfield, Pink Floyd, Alan Parsons, Moody Blues, Grateful Dead are some that I have that sound much better in multichannel. Lyle Lovett (Joshua Judges Ruth) is much better sounding in surround and so is Alison Krauss and Union Station Live. Norah Jones, Diana Krall, Natalie Cole and another Alison Krauss I have sound good in both and depending on mood and whats going on, I seem to play both ways. Lots of stuff I would like to hear in surround some day: Dead can dance, Michael Hedges, Brian Eno, Enya, Peter Gabriel, leo kotke, all the pink floyd stuff. I guess there may be no correct answer as to which sounds better or works better as it would be a matter of the type of music which may lend it's self to one or the other, or both even. It's a great time to be an audiophile.
Springowl, if you're still out there, you must have upgradded by now. It seems that your original question was about improving upon your av-receiver as a pre-pro. I have a similar set up and I have thought long and hard about how to make the most cost effective improvements. I have two differing approaches.
1. Buy a Classe SSP 30, it will improve everything, with one purchase, especially the 2 channel.
2. Get a good CD player with a volume control, and a digital input. This will bring greater 2 ch improvement and make the DVD player sound better on PCM sources, like concert videos.
My plan is to go for #2, I want to make my stereo sound the best that I can afford, with the home theater side making small gains. I love the way the HT sounds now anyway!
I will also be upgrading my main amp very soon, I would like to get that and the CD player together. My choice for the amp will be the Spectron and probably Resolution Audio CD55 for the source. I will still consider the Classe as an addition, but not this year.
I have developed a hybrid of the two that, in my opinion, is better than either 2 channel or multi-channel. I have a 2 channel CD going through a 4-2 multi-channel stereo system. There is no multichannel processor to screw up the sound. The 2 channel music goes through two pair of identical speaker drivers (Klipsch Heritage)positioned at the front and back of the room powered by two identical ML stereo amplifiers. A pair of TacT W410 subwoofers are positioned in the corners to povide the deep bass. Three preamps are used so each speaker is controlled individually. The preamps are connected in series so all speakers can be controlled simultaneously by the first preamp. All preamps are passive so only resistors are used to control the volume. Placette preamps are used to to provide the cleanest sound with no added distortion. The back pair of speakers are raised to a level which is hardly noticeable, but provides a three dimensional sound that is out of this world.
The only reason 2 ch is better then 5.1 is becouse we (you at least) all live with missmatched speakers.
Have you noticed how in recording studios all 5 speakers are the same?!!!!!

Well actually there is one other problem. Most 5.1 mixes just plan stupid. When was the last time you sat front of the drum kit with the keyboard in the far right behind you and the jazz chorus coming out of ..humm...everywhere????