I have not spent a lot on audio gear and I have a very nice sounding system or two. But I have heard the big systems and there is no comparison. If you want to run with the big dogs you have to spend some big dough. Diminishing returns, maybe that's a thing but it takes big bucks to get to the top levels. Same as any other thing one might do.
P.S. However you can put together a very good system that most people would find extraordinary for the price of a modest car.
P.S. However you can put together a very good system that most people would find extraordinary for the price of a modest car.