I mean, I don't think the R&RHOF NEEDS to be a strictly-rock institution. Celebrating other kinds of music like pop, soul, blues, R&B, etcetera, isn't a bad thing. "Rock n Roll" is a pretty broad term nowadays. "Rock Star" can be used to describe anyone from 50 Cent to Chad Kroeger. Its just the word that's gotten a bit broader in usage. So what if they let in Madonna or the Beastie Boys?
Also, Black_Floyd, you're sounding like a butthurt pretentious prog/metal fan. Just thought I'd let you know before you said anything more embarrassing.
Besides, you left out all the old guys making hard rock music in the style of Mr. Big or Extreme in the late 80s/early 90s but without changing anything. Or, you know, plenty of the amazing modern bands that can be considered "rock."