Neil Diamond is a defensible pick. I know he wrote tons of hits not only for himself, but others as well. However, my main beef with him is that he's just as much contemporary pop, folk and country as rock. But, once you've accepted Madonna and Donna Summer as "rock", then Neil Diamond fits right in.
But, as you old fogies on this thread demonstrate, hard rock and metal acts are woefully disrespected and underrepresented compared to other genres. Even no brainers like AC/DC and Black Sabbath took far too long to make it. Rush is fourth behind only the Beatles, Rolling Stones and Kiss in gold and platinum records for a band and they aren't even eligible yet! Hell, I do not like Kiss at all and it's an even bigger joke than Rush that they aren't in either.