I have thousands of tracks of music in my library. I listen to only a fraction of them at the proper volume level, the rest are occasionally played when I am in the mood, but rarely at a good level.
They are poor recordings.
The shame of it all is that many of the musical greats I listen to fall into this category, becoming more background toe-tappers than foreground jaw droppers.
Perhaps it's the same with your library. The great ones, both musically and sonically, get the most play. The others, musically great but sonically grating or flat, get the least play and always at less than optimal levels.
If you think about it, this dynamic is one of the reasons remastering services, like Mobile Fidelity, exist in the first place. Some great music can be saved by careful attention and skillful twisting of knobs on the mastering console. But most never get this attention lavished upon them.
I suppose it's accurate to suggest I've come to grips with the notion not all music can be enjoyed at the levels intended, but that's ok.
There's value to background music.