Quality system, make poor recordings sound better?


I notice that as I move up the audio chain, poor CD recordings sound worse and the good ones sound superb, should this be the case? Also I on any given day my system sounds different even with the same CDs. Any thoughts on this as well?
phd
11-06-14: Maplegrovemusic
can someone who feels as the op provide us with a recording you think is poor . i would like to play it through my system
Although most of my listening is to classical music, I'll cite some examples from among popular recordings that happen to be from the 1960's, from artists I particularly like. All of these recordings are available on CD:

1)The Blues Project, "The Blues Project Anthology" (2 disc set on the Polydor Chronicles label). Particularly the first nine tracks on disc 2, which originally comprised their "Projections" album.

2)The Seekers, "All Bound for Morningtown; their EMI Recordings 1964-1968" (4 disc set on EMI).

3)Matt Monro, "This is Matt Monro" (2 disc set on EMI "Music for Pleasure"). I'm referring particularly to the instrumental accompaniment, not to the reproduction of his voice.

I'll add that I would resist any temptation to blame the 1960's technology for the disappointing sonics of these recordings. As evidence of that, the Chesky remastering of the 1962 recording of Dvorak's "New World" Symphony, performed by the Royal Philharmonic Orchestra conducted by Jascha Horenstein (Chesky CD31) is easily among the very best recordings I have ever heard, and shows what the technology of that time was capable of.

Regards,
-- Al
Thankyou all for the great indepth answers. A few days ago my
daughters boyfriend brought over his IPod and connected it to
my main system. He was thoughtful enough to have downloaded
some of the music I like, new and older recordings. I thought
all the music played sounded spectacular. There wasn't that
big of gap in sound quality between older and newer recordings
that I experienced with CDs. Go figure. I think maybe I should
get an Ipod as a source for music.
Digital complicates things a lot in that there are unlimited ways any particular digital audio files may have been processed at various points in ways that have major effects on sound quality. The differences will no doubt be subtler
played on lesser equipment but more significant as the playback system gets better.

For example, there is much less difference between my best digital files and my worst(all lossless FLAC, a few converted from lossy compressed mp3 file download) played back on my Sangean WR-1 table radio, my least hifi playback device, though no slouch as table radios go, compared to played back at home via my main rig laying on teh big OHM F5 speakers. I have a half dozen or so other options in place for playing back those files concurrently. The others all fall in the middle somewhere in regards to overall sound quality.
the recordings must have sounded good to someones ears . more than one set of ears will hear a recording before it is pressed . how does a poor recording get let by ? cheap radio shack equipment in a major studio ?
bands can take years in the studio to make records. you think they are going to let crappy produced music out ? There has to be some kind of quality control. Some times it gets redone by a different producer if the record company or artist is not happy with the final product.