Correct.
Audio is a rich vein of consumer products with almost a hundred years of history, similar to jewelry, firearms, cameras/lenses, hamburgers, and all sorts of stuff. It just kind of ended up this way. Money makes the world go 'round.
More expensive parts, better build quality, higher labor costs, all of which makes sense, plus a lot of effort towards brand prestige, etc. The truth is that there really is no direct correlation between cost and performance above a certain level, with many examples of high cost duds, and modern hypex and purifi based amps offering SOTA performance that's down right inexpensive.
It's not quite that simple. That is getting into "all amps sound the same so why doesn't everyone just get a Walmart cheapie" territory. It's just not true that all amps sound the same. What is true is that amps with low distortion, low output impedance, linear response, and operated within their limits tend to be indistinguishable. But there are some wooly amps with high distortion. There are amps with high output impedance (pretty much every tube amp, older gen class d, and a slew of oddballs from the periphery like some Nelson Pass designs), which will not be linear into a varying load (any speaker). Even well damped amps may not be load invariant into reactive, difficult speaker loads. And clipping happens far more often than many folks realize.
Pretty much. That's why we often recommend devoting the bulk of the audio budget towards speakers. It's where the rubber meets the road. After that, clean watts are clean watts, so it's a matter of balancing "too much is just enough" (no clipping, ever!) with "unused power simply goes unused" wastefulness. Unless your room is huge and/or you're an extreme headbanger, the amp you chose seems like it will fall into the "just right" range.
