Would a 15yr old Pass walk all over a Anthem STR Integrated? No, not in my opinion.
I have the STR Stack and I’ve been very happy with the sound. Having ARC takes things to a whole new level when used properly. I have a decent sized floor stander in a small(ish) room (see virtual system) and having the ability to manipulate the sound to my taste and not overloading the room is great. That said, even without ARC I would still take the STR because I like the Anthem sound.