But what does 'good enough' mean? There aren't absolute standards of good and bad in music popularity: there is only whether you're popular or not.

I don't like the music of any of the current crop of big-name folk acts who can be said to be 'successful'. I'm not mentioning any names. By my standards, they are not 'good enough'.
They are not without talent, but that has nothing to do with their success.

Their success has to do with their very particular sound, and how they look and, yes, determination and luck again. If their music has anything in common, it's an agglomeration of unpleasant musical tropes known collectively as 'crossover appeal'.

Conversely, the folk musicians in Britain who make in my opinion the most successful art (and who I'm happy to name: Alasdair Roberts, James Raynard, Nancy Wallace, Michael Rossiter) are not in any danger of troubling the pop charts. Entirely uncoincidentally, they have none of those unpleasant musical tropes known collectively as 'crossover appeal'.