I don't think that "sound the same" is what many of us are talking about.
In the world of speakers and rooms, nothing sounds the same, even the same system from a different part of the room.
I'm sorry but you keep missing the point I made when referring to speakers. Like I said, speakers sound very different to each other. Heck, they even the same speakers sound different if you move them around in the room. It's electronics like amps and DACs that all sound similar to each other.
I am not sure what you are getting at. I'll repeat what I said for the third time:
Electronics such as amps and DACs make very little, if any difference to the end sound quality, assuming the units are working properly and within their design spec. IOW they sound essentially similar and can not be reliably distinguished one from another in ABX tests.
Speakers are very different to the above and one set of speakers will usually sound very different to another set, especially when used in different rooms. Even the same set of speakers will sound different to itself when they are moved around in the listening room.
The two statements are both correct and not mutually exclusive or contradictory in any way. Because speakers/rooms sound different to each other that is no reason to have amps that also sound different to each other, and indeed they do not when properly designed and working (as most are these days). Just because speakers sound different to each other is no reason to want your amp to act as an additional tone control and introduce further distortion into the chain.
Yes, everyone with a decent modern SS amp working to spec is achieving it. Even those who spent $10,000 on their amp (usually).
WRT to speakers and room, I only use my HT for movies and I have calibrated it to Reference standard using treatments, automated RC, REW measuring software/mic, EQ, speaker and sub placement etc etc, and I have chosen subwoofers and speakers that are universally acclaimed. That's all anyone can do. If you take as much time and trouble (and you are primarily concerned with movies) then indeed you can do the same. It isn’t a "secret" as such. Aim for reference level SPLs, which means powerful amps and speakers capable of handling the power, and a flat frequency response 30Hz - 20kHz +/- 3dB.
I suspect you are not being serious and just looking to argue, so I won't post on this any more. I think I have made my view clear.