The trouble is the the definition of what type of music Rock N Roll is has changed,
In the 50's the like of Elvis, Chuck Berry, Jerry Lee Lewis were regarded as rock and roll. Then the Beatles (who were more pop orientatated in the early days). The Stones/Kinks/Animals were more rock/blues orientated.
For me the likes of rock began with Zeppelin, Deep Purple, Black Sabbath, Rush. Punk then took over for a short period. Then what is regarded as metal began with the likes of Priest and Maiden.
But with regards to the Rock and Rol Hall Of Fame, it embraces all types of music.
Perhaps a separate rock/metal hall of fame should be set up.