For me, the question is the building process leading to a satisfactory system based upon individual choices and external factors. After much research and years of listening, I found myself in the position of having the means and time to create what for me was / is a system where I am no longer chasing the last 0.05 percent.
Financial considerations create a range for most all of us. The next important part is the WAF factor in terms of what our system will do to the living area. The dedicated listening room is not the norm for most people.
I found that the speaker drove the amplifier choice. I went through a few amps before finding my keeper. Source is important, but I agree that room treatments have more effect on the sound. I would argue that quality source material is as important as the source playing it.
I have found that other tweaks are really at the margin to my ears, useful, but nothing to break the bank over. I do have dedicated power circuits due to the requirements of my amp, but also have an 86 much TV in the room that does impact the sound a small bit, but keeps peace on n the family.
Everyone has a different journey, I have found mine to be very pleasing sinceI quit changing gear all the time. Now it is all about listening to the music.