Shallow? Slipshod? If relevance to the modern world is so lightly dismissed folk will die out with the current generation of historiographiacally suspended enthusiasts determined to posit 'folk' in their own temporal fantasy.
Who has given anyone the right to say what folk is? When was this distillation of national verisimilitude decided? Was the music that went before irrelevant because it didn't exist on an aural record? Folk by your definition is as authentic as druidry, costume cosiness for the disaffected.
Folk is whatever anyone with the balls to stand up to self-styled academics says it is. The points are as meaningful as shouting 'Judas' at Bob Dylan, a fifth-time removed songwriter castigated for having an electric wire dangling from his guitar.