Drum do have a place in folk - international folk, that is. As in African drum music, or Korean or Japanese drum music, etc etc. But closer to home too - there are types of Greek/Albanian/Bulgarian/Turkish music that without the drum (be it a big fella or a little toubeleki) would sound "naked". There are African war dances that without the drum would look silly.

It's just an instrument, with a role to play. And now and then, a well-played solo can be enhancing.

I remember the Chieftains doing a "duelling bodhran" number that was wonderful.

And for the definitive use of drums alone to create music (in my book) listen to Flairck's "Het Debat" from their album "Bal Masque".