Again i feel this is where quality control comes in, and much like taste is highly subjective. To explain;
Now records shops, and i'm talking about that place where you had to physically go into, and talk to the owners, or in the good ones (like Smallfish) they talked to you, there was a sense of community, all sharing a love of great sound. This real interaction, really helped know the good from the mediocre, you listen to it, try another, debate it. With this community moving to the internet and even then almost moving away from there too, the only place left for this assurance is with the labels. I have been a follower of 12k for many years, and it is this following where i can judge in my own mind, a sort of dialogue with the styles 12k and other labels put out. I get a sense of how the sound is changing, developing or not by following a kind of taste, that of Taylors, to some degree, but also something that fits a model, that of 12k or Line. With this i can compare to previous releases, other releases by that artist on other labels and all manor of ways that go to create in my mind something to judge what i perceive as a quality release or not. To say it is only the music that does this, i just simply don't believe it does, it is more than that, and a label does a great deal towards knowing what is good or not.
Having said that, there are many labels, that i can't really consider a proper label. They pop up everywhere and disappear just as quick, and it all seems a bit reactionary or following that trend, or a case of, "nobody will release our stuff so we will do it ourselves", and perhaps that is where the mediocre comes in.
A label is an identity, a belonging to like minded people, a family or less or more experienced people. Without the label everyone would be fumbling around in the dark.
It is labels like 12k and Line, no actually it was the label 12k and Line that kept me going, that still keeps me going today.
I must say i am a little worried that such a question was even asked, if 12k or Line stopped, which i suppose they will do one day, well, i dread to think about it.