I just don't see how most normal houses (3/4 bed estate) will accommodate.
Atmos and as such mass appeal will be difficult.
It's appeal may be practically limited, but I might suggest that most of this kind of stuff is bought by men, who are often suckers for all the latest features. i.e. I might not be deploying height speakers *now* but I might next year and my amp/processor should support it now just in case. It's also somewhat of a bell-weather for how well supported a product line is.
lets not also forget that many purchasers will be in the states where houses are often much bigger, and more accommodating of a more involved system.