Lots of this stems from stereo only days. I know one of my setero only set ups had monoblack Conrad Johnson Amps driving two big Maggies. Sounded really good, too. That was a time when there was no serious multi-channel systems out there. And, the steps had to go through to get decent sound were affected by a whole lot....cartidge, turntable, quality of the vinyl pressing, cleanliness of the vinyl, turntable and cartridge mounting, pre-amp, amp, etc, etc, etc.
Today, there are a whole lot of audio sins that can be forgiven by including a good DSP chip set and accompanying correction software that come with AVRs.
There's also the point that amplification has become a whole lot more efficient.
Most of the pieces from the high quality manufacturers (i.e. Pioneer, Denon, Marantz, Yamaha, etc) sound good. Generally speaking, the more you spend, the more compute power you get, the more absolute power you get, the more switching that's available, the better the software is, etc.
I'm currently running a Denon 4311 driving 7.2 channels using Audyssey XT32. My room, my HT, even the DVD-As/SACDs (hi-rez music that is far superior than my old analog set ups) I listen to have never sounded better.
That said, feel free to experiment. Buy some pro amps and hook them up. See what you think (I did a few years ago...I have Crown pro amps in some boxes). I have an Emotiva amp sitting in my "toys" closset awaiting duty if I ever see fit. So far, no need.