An acoustically well treated room can make a much less expensive system sound far better than a much more expensive system in an untreated room. Acoustic treatment, done properly, can leave you wondering why you thought what you listened to before sounded good. Most of us must be satisfied with less than ideal room acoustics for a plethora of reasons, but appreciating the essential principles of room acoustics can improve the comprimises necessary.
If you have a nice system why do you really need room treatments?
Yeah you may need an absorption panel if your room is completely open, ie. No rug or furniture, ie just lonely single chair. But if your system can't cut it in any room then it's a system problem and you should be able to discern a good system regardless of the room. Unless you put it on the roof of your apartment building but the Beatles seemed to have survived that effort
I think people go nuts with all this absorption acoustical room treatment stuff and it looks kind of awful. Once in a while you see a really cool looking diffuser panel and I would definitely want one. But to have a system that works really well without any of the acoustical panel distractions is a wonderful thing.