As far as I understand & know back when the early Coppers sung in their local pub after working in the field they didn't sing from notes. They just sang & the little ones learned at their fathers feet & in time their children learned at their feet. If you want to have a good sing & keep it, you'll need to make sure you keep the good singers from going off elsewhere & make sure that they pull the rest along for it's own sake of survival.
No, not every good singer is or wants to be a performer but we all want to have a good sing when we go to sing, if you're happy with a mediocre or sucky sing, well so be it then.

Barry