One of the traps that we audiophiles fall victim of is that we often do not prioritize the musical merits (performance values) of a recorded performance as the focal point of the listening experience. Instead, we focus on the “sound” of that recording and then, if only subconsciously, compare and judge the quality of that sound relative to what is possible…the sound of the truly great sounding recordings. So, as one’s system evolves and becomes more truly transparent the sound of deficient recordings may be perceived as “worse” because the sound of truly great recordings has been revealed to be even better than previously thought. The bar has been raised, but this doesn’t mean that the sound of poor recordings is now “worse”.
For me, taken on their own merits (and with some exceptions as pointed out by mikelavigne and others) “poor” recordings can often sound better on a truly great system; in great part because more of the musical details of a good performance will invariably be revealed.