I know that your room and your speakers are both like wicked uber-high end. For the general Joe Schmoe, do you think they'd get as good of a "surround" effect with a 2.1 system?
I don't know what it would take, but if the acoustics are good, the speakers have good midrange accuracy, and the imaging is as it should be (a result of good midrange and good acoustics), then I think so.
My secondary system consists of a small pair of bookshelf speakers in a far less ideal room. I do have good placement and listening position. When I pay attention, I get a solid "virtual" center channel and some of the surround effect I talk about with my high end room/system. However, I don't generally watch shows with a critical ear on that system, so I cannot make a perfect comparison. Perhaps if I played the same content and paid very close attention I would discover a similar effect.
But my point is that people go to huge lengths to get the expensive gear and 10 speakers crammed into their room to have a serious surround sound experience with the intention of making movies more enjoyable to watch, right? With that much effort going into the "buy more and more and more until I am impressed by the results" approach, one could just buy less and better speakers and gear and put similar effort into getting good sound from two speakers rather than finding a way to cram a dozen speakers into a room in relatively good locations.
So, your question doesn't reflect a apples to apples comparison of someone with a 7.2.5 system with all the electronics and energy and time it takes to make it work well versus someone with a pair of high cost speakers placed as perfectly as possible and as little gear as necessary to make them sound their best. Neither of those people are the proverbial "Joe Schmoe" who doesn't know what they are doing. If one is going to spend $4,000 on the audio portion of their system to get the best experience, I am arguing that a great pair of high end speakers and a good amp are a better choice than a complicated receiver, two subs, and 12 speakers scattered all over the room.
But, as I mentioned when I started this thread, it is less about the surround sound "effect" that drove me to abandon surround sound. It is much more about how I enjoy video content and the realization that a dozen surround channels doesn't make a good show with great story-telling, acting, and even action much better and it can actually distract from the things which make shows the most enjoyable.