I am not sure if I totally agree with that or not. I'll have to ponder it for a few days and then come up with a witty answer!

I do know that my son-in-law's Irish band plays some old tunes that sound a lot like bluegrass. The old timey and bluegrass music has a lot of roots in Irish music. It's all logical, but it took me years to figure this one out.
I am not sure where Kid Rock fits into this one, but I'll think about it...