Link seems to be broken.
That link works.
Obviously the AVR needs to accommodate more components like AM/FM tuner, video upscaling, digital processing circuitry, front panel screen display, and of course other channels. That must come at a cost to optimal 2ch design and implementation. i.e reduced channel separation and a sacrifice of capacitors for lack of available space.
Seems like a very weak argument. Heavy on intuition and very light on facts or evidence. You seem to have a very low opinion of modern technology. I'm an EE with over 40 years of experience with audio and I know of no reason why what you say has to be true.
The specifications for my Perreaux pre-amp have much lower distortion figures than my Yamaha 1065 and also higher maximum output voltages on the pre-outs. Clean high output voltage peaks on the pre-outs must be beneficial for the leading edges of notes that quite often demand a sudden peak compared to the rest of the note.
Again, the use of that word "must". Fact is that just about every audio power amp in the universe can be driven to full power and even into clipping with only about 2 volts or less of audio. Apply more, and the amp clips.
I have SS preamps that easily put out more like 8-10 volts and tubed preamps that put out 30 or 40. That extra output voltage serves no practical purpose at all because every power amp I have clips with less than 2 volts at the input.
A preamp that puts out 8 or 20 volts when hooked to a power amp is like a car with a big engine and narrow tires. If you gun the engine you get a lot of wheels spinning and smoke, but if anything you would do better to modulate the throttle and improve the traction of the tires.
This may be the reason alone that makes my 2ch pre-amp sound more dynamic and the AVR flat in comparison in 2ch playback.
I don't doubt that you perceive those differences, but in many cases they are due to listener bias. It is intuitively clear to you that the extra output voltage should make things sound better, but that may only due to your lack of a good technical education and actual hands-on experience with technical tools. If you understood how these things worked and actually measured voltages and looked at waveforms, the things I say would become abundantly clear.
Now I'm not just some kind of 2ch snob that turns my nose up at AVRs in general.
So you say, but the lack of an actual viable technical argument and relevant facts and figures tells a different story.
It's more about the music and I couldn't care less about the gear that achieves the results I am after. A wide 3D soundstage with good separation and localisation of each instrument and vocal has always been important to me.
That does not make your goals as a listener any different than mine. For me, knowing about the gear is only a means to the exact same end that you are searching for.
As such I actually use my AVR for 2ch music, but played back in 5.1 with the AVR's processing. The AVR has many advantages like sub integration with phase and crossover and balance and distant settings as one example.
I have audio systems with AVRs and I also have audio systems that are very much 2-channel only. I have to admit that I don't use my multichannel system's facilities to synthesize multichannel out of 2 channel material.
I have found through lots of trial and error and experimentation that the soundstage with the AVR's 2ch playback was somewhat flat... through a 2ch pre-amp was a lot better and was something I could have lived with... and with the AVR's 5.1 it was a bit better again, so I now use that.
In my multichannel systems I accomplish that by setting them for straight 2-channel operation.
So if it was strictly to be a 2ch system only, then I would be using a 2ch pre and power or integrated only and no AVR in the room.
I do that too. I also have at least one system with a two channel receiver as its centerpiece. I have found through long experience that a good receiver can sound just as good as separate components, which I also have plenty of.