In a poor recording a system can't reproduce something that is not there. An "accurate" system will play the good and the bad. It is not designed to fix the bad just reproduce what is in the recording.
Can a great system make a mediocre recording sound good?
I spend a lot of time searching for well produced recordings as they (of course) sound so good on my system (Hegel 160 + Linn Majik 140 speakers). I can't tolerate poor sounding recordings - regardless of the quality of the performance itself. I was at a high end audio store yesterday and the sales person took the position that a really high-end system can make even mediocre recordings sound good. Agree?