addressing some of your points:
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noise level and being audible: yes, in headphones and good speakers, you can hear these things. as each stage improves (the dac, the pre and the final amp) you do hear more of the recording (which most people do consider a good thing). and yes, 130db down is still audible in headphones on classical music that has good dynamic range. its not flat 130db either, that's a best-case null point. on average, things that are 'good' these days tend to be 100db or better but that's a real honest 100db, not some marketing specs.
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upper frequence response matters. you need a few times the audio passband worth of FR to pass the audio band cleanly. modern pre's tend to want to have good response up to 50khz, 100khz and beyond just so that the '20-20k' gets thru easier. send a square wave thru at even 10k and watch it as it goes thru a high bandwidth amp vs one that is 'just enough' to pass 20k. the fidelity of that wave is visible on any scope.
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0.5db steps, it matters to get you a smooth transition as you vary the knob. I tried single db steps (for almost a year, on one of my protos) and thought 1db was pretty ok for daily use. then I built a half db stepper and liked it a lot more. costed 1 more relay and a few more resistors. was worth it. and for a subwoofer box, I built one that uses 8 relays and only gives 25.5db for total range but it moves in 0.1db steps. yes, for a subwoofer level control, you do want that level of granularity. try getting that from your sony
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re, high end spkrs; yes, I have looked at the FR graphs. some of the modern tweeters are truly amazing. you can buy tweeters for $50 or less that are flat out to 30k. modern tech is WAY beyond what we had even 10 yrs ago (its a good thing, btw). along the same lines, if you use good headphones (my ref pair is sennnheiser hd580 and hd650) you will hear every little detail and it will be quite flat sounding. cheap speakers and phones are limiting but modern systems are not.
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servo speakers; not necessary. even conventional cone (boring) spkrs are very high fidelity these days. I think you're just quite out of touch and not willing to update your world view, sorry to say. a LOT has changed since the days the dinosaurs walked the earth. old classic gear can be treasured for its 'sound signature' but performance wise, its usually not competitive. there are a lot of exceptions but I would not consider a mass market sony box of any kind - no matter what the company claims - to be competitive with custom made DIY audiophile gear. for lots of reasons.