Are you kidding? This stuff is immensely popular. I haven't heard one person say he didn't like Andy McKee.
I can't say I'm convinced, I've never seen any of his CDs in shops (although i havent been looking for them), I've never seen him on telly or in the paper, and I've never seen anyone sporting a T-shirt with his name on.
Immensely popular maybe, but only on YouTube.
P.S. I don't like Andy McKee