Phish. Say what you want about their music, but no one can deny their massive fan base, tour profits, and impressive repertoire.
Chicago totally rocked, far more than 20 yr inductee Madonna
Amen - anyone in doubt only needs to check out say, the first 10 albums or so.
Chicago was founded as a hard rock band with horns, and that is precisely what it was while Kath was alive.
Sure, some of their later stuff is ballad-heavy, but they sold a TON of vinyl, and they are LONG overdue for that POS known as the R&R HOF.