I would tend to agree with your assessment. I suppose some would disagree, but, in my view, unless you had a situation such as when DD and DTS came in to existence in movies with discretely recorded LR and RR channels and later along with the additional channel in the rear, I am not sure what the benefit is other than adding another couple of amps much along the line that Yamaha has done for years with their "presence" channels. This just extracted "out of phase" sound or added delays and/or reverb to give a more "spacious" presentation. I would assume this would also fall in to the category of what PLIIx or Neo6 or Neural THX does when extracting additional channels out of two or adding the additional rear channels to 5.1. I find it kind of funny but some of this stuff is kind of "deja-vu" all over again. Before the rear-center channel came in to existence, SRS labs had a box that in addition to extracting sound from the LR and RR speakers to make a rear center channel, it also could be used to extract sound from the FRONT L/R speakers in which you would add an additional amp and two speakers to mount on the "ceiling" overhead to give more realistic pans from front to back. At the time, it never really caught on.

I guess it all depends on how many more speakers the potential purchaser can tolerate and the potential benefit which is adding more features to the unit and increasing the cost.

I suppose it might change in the next generation of equipment but it is interesting to note the only manufactures that I have seen that have gone this 9.2 and up route have been Onkyo/Integra and Denon. I am not sure how they are doing it but Marantz in their newer 5004 and 6004 AVR's has implemented PLIIz in their second set of front L/R speakers but it is still a 7.1 configuration without the extra pair of amps.