They were two of the best of all time. Emmylou Harris & Roy recorded some together. She said Roy was one of the kindest men she had ever known. They recorded "Loving you feeling again " which was one of her favorites & mine. Musicians back then were true musicians & what you heard didn't go through a synthesizer or have computer enhancements. I doubt many of the stars today could pick up an instrument, play & sing without help from a machine of some kind.
Roy & Johnny were just two to come out of Memphis. Jerry Lee Lewis & Carl Perkins were two more that come to mind. The Beatles said a lot of their music was inspired by the Memphis artists. Carl Perkins was a guest of the Beatles on an island resort they owned. Carl said they spent many hours just "Jammin". I think "Matchbox" was one of the Beatles favorite Carl Perkins songs. They admired the simplicity of the Memphis & Delta sound.
Whether one like the Beatles or their lifestyle you can't argue that they were real musicians at least in the early part of their career.