One reason why the old songs have survived is that they ARE (timelessly) relevant.

I think the summary of this thread is
(1) [type of music I like] is good
(2) [type of music I don't like] is crap
(3) I'll prove that by citing imaginary examples of bad performances in category 2

Two can play at that game: I'll see your "whining out of tune voices" singing trad songs and raise you a club full of whining out of tune guitar-toting navel-gazing failed-pop-singers with their self-penned drivel... but so what? Neither attitude (and both are clichés of course) proves anything. I've heard plenty of good and bad examples of every kind of folk music.

But in a club, session, singaround, open mic or whatever, it is a good idea have some sensitivity about what's expected. Some deliberately have quite a narrow focus, others welcome variety, all of which is fine, as long as you know which it is going to be. I know which ones to avoid because I won't enjoy it or fit in.

Anahata