Dave, there is a very good reason for your confusion, and you stated it quite well.
Tech Talk is the name of this forum; that means we know a thing or two about how to get class "A" sound out of less than class "A" equipment.
I will give a limited example of how we get Class "A" sound from components that may have began as class "C" components, but that's taking it a long way; it's easier to turn Class "B" into class "A"; but when you think about how much cheaper Class "B" is than Class "A"; that's still taking it a long way.
First you must know what Class "A" sounds like; while I know because "high end salons" existed when I went on my "pilgrimage" to those places to discover and differentiate between the different classes. I don't know how it can be done now.
But that is the beginning, as an example of some of the things I have done; I made my own interconnects; Belden had some wire they sold to radio and TV stations they used for interconnects, that was a copper and silver composite; they sold it in 100 ft reels. (they no longer sell that to individuals, I wonder why not?)
New wire for tonearms is a good tweak. There are many useful tweaks for TT's that can be found on this forum that will bring them up to "B" if they started out "C", and that's a big leap in price. You will have to bite the bullet on cartridges.
Of course you have to be a technician to attempt my latest project. (those monoblocks sound so good now, that I'm in no hurry to upgrade the capacitors) which is not only to change the capacitors, but to modify the cabinet the unit came in.
There are limits to what I can do; TT tops out at Class "B"; Class "A" for amps and Pre's that began as Class "B". When you add up the money for interconnects, it comes to quite a bit; fortunately I have enough of that Belden wire to last a lifetime, but "Vampire Wire" sells some good wire, and everything you need to "roll your own". That concludes everything I can think of for the moment.
We're on the same page, and I concur with your list.
Enjoy the music.