CD playback, DAC vs. op-amp/discrete components, and the advances? Where are we?

true, all audio components sound different - even if intended for the same purpose, same specs or very close etc.

in terms of improvements, I am moving away from his hobby. Instead of chasing this audio butterfly, imagine just being able to enjoy music on anything. That's my goal now.

What has been your experience with what makes for improvements in digital playback?

The return of LP sales (now outpacing CD sales) proves no amount of "rez" can put back in what was left out. For me the "evolution" is going beyond 2 channels to immersive audio (NOT to be confused with surround sound".