After spending a lot of time with a $500 Onkyo 7555 cd player that I loved dearly, and then listening to a bunch of $1500-$5000 cd players and settling on a Marantz SA-11S2, I can safely say that:
1) No two cd players sound the same. If you think they do, go back and listen some more.
2) Expensive machines usually - usually! - sound better (more detailed, more refined, more dynamic, better bass and bass definition) than cheaper ones. Larger power supplies, the design of the output stages, isolation and vibration control, transport design, and so on, all affect the quality of the sound and all cost $$$.
3) Mass market DVD players used as cd players sound like s***.
4) You need to "taste" cd players the way you would lollipops, and find your best "flavor" or sonic signature, because they are all uniquely voiced.
5) The $$$ required to get these last ounces of quality out of a cd player are, for the average person, probably not worth it!
That's why they're referred to as "average people." And I don't say that as a knock. I think that they probably are happier than those driven by perfectionism.
I also think that they probably aren't hanging around here...........