Akshually... Styx has two original members left. JY and Chuck Panozzo. However, Tommy Shaw is practically an original member, kind of like Gilmour not being "original" in Pink Floyd but close enough, and an integral member for all their significant stuff. And continuing with the analogy, is Styx without Dennis DeYoung kind of like Pink Floyd without Roger Waters? It might be better. The Shaw/JY songs have held up much better.
No longer a huge fan, and never seen them when I was, I'd still check them out on a lark, in a hassle-free venue (not Jiffy Lube). They'd be a great Birchmere act. Also, Foreigner is almost Starship-level bad, nails-on-chalkboard bad. That's enough to keep me away.