I say put the non-rock and roll performers in as “influences” but not in the hall proper.
The rap, disco, and country halls of fame won’t be inducting pure rock and roll artists any time soon.
How does ABBA qualify as an early influence? You think a new category should be created? I disagree.
It isn’t about about what you like. The Beach Boys are not closer nor more distant from “Rock and Roll” than ABBA. And ABBA is arguably closer than Johnny Cash.
Perhaps you should get busy on having the following past inductees tossed out of the Rock and Roll Hall of fame then:
The Beach Boys
Woodie Guthrie
Bob Dylan
Louis Armstrong
Johnny Cash
Good luck w/ that.