The article just shows great guitarists and what they did to become learn. They also show what these guitarists contributed. In order to be a great guitarist, you need good rhythm. If the rhythm you are playing is bad than the music is bad. You should learn 3 chords. If you learned 3 chords you could play a thousand songs.
Read the full article here:
GuitarPlayer: The 50 Greatest Rhythm Guitarists
