I use bad recordings as a yeardstick to tell me how I am doing. IME, a system can 'editorialize' and can often react poorly to poor recordings, and also recordings with lots of energy.
An example from the old days was Village Music of Bulgaria on Nonesuch LP. In the old days my pickup had real problems with the intense vocal expressions on the LP and it sounded terrible. As things have improved, I have found this LP to be astonishing- dimensional and really well recorded.
From this and other examples I don't buy the idea that bad recordings sound worse as your system improves. A good system will take the bad recording in stride and will present what is good about it as well as what is bad without comments of its own. The smoother your system is (IOW: the less higher-ordered harmonic distortion it has) the easier this will go for you.
An example from the old days was Village Music of Bulgaria on Nonesuch LP. In the old days my pickup had real problems with the intense vocal expressions on the LP and it sounded terrible. As things have improved, I have found this LP to be astonishing- dimensional and really well recorded.
From this and other examples I don't buy the idea that bad recordings sound worse as your system improves. A good system will take the bad recording in stride and will present what is good about it as well as what is bad without comments of its own. The smoother your system is (IOW: the less higher-ordered harmonic distortion it has) the easier this will go for you.