Doesn't surprise me at all that he outsells lots of pop acts. He has a corner on the senior market. My wife's parents went to a Gaither show in B'ham and said they felt like they were the youngest ones there. They're in their 50s.
He's been writing music for going on 40 years and is still going strong. There's a DVD/CD industry behind these shows that you wouldn't believe. It also wouldn't surprise me if the Gaither CDs and DVDs outsold pop acts.
Gaither also isn't a "Christian" artist with any sights on branching out (a la DC Talk, Jars of Clay, Amy Grant, Scott Stapp, Lauryn Hill, etc.) into other types of music. Most young kids up to thirty-somethings in my church have never heard of him either. It's no wonder to me that most people haven't. He targets an older, affluent, very religious audience and targets it well.
~Jamie