Jerry - interesting. Got me to thinking about it, too, although I'm not a gospel singer. I would think there are two possible reasons for singing gospel unaccompanied -

First, the church might look askance at instruments -- the fiddle being called the "devils box" and the banjo seen as a racous tool for frivolity, drinking, dancing -- and not want their sacred music associated with "bad" music.

Second, simple economics. I suspect many gospel singers don't come from money, and, in times past, couldn't afford even a simple instrument.

What do you think ?