Reso guitars appeared at about the peak of the jug band craze. Perhaps the jug band men could not afford one at first & didn't really need one like the solo/duo blues men did. Out of the well-known recorded musicians, the jug men worked day jobs & the blues men may have been more dependent on their income from music, so invested more money in their guitar sometimes. Big Joe Williams was an exception though: his guitar was a mess, the back was loose, & he kept his possessions in it.