I install a fair few playbar/sub/surround setups for my customers, A lot prefer it to dedicated speakers and an amp due to the minimal disruption to the decor to hide wires etc and the sonos sub is a gorgeous looking thing which appeals, but when I have a customer with a taste for more bass than the sub can deliver or a slightly oversized room it seems a terrible shame I cant add more than 1 sub to the room. Is there some technical limitation, or is it just a policy decision?
To me it seems a no brainer to add the feature if its technically possible, it would be an easy way to sell more subs no problem, and would mean it would be an easier sell to put sonos in instead of an av amp.
I have done a couple of jobs with hdmi amps feeding in wall speakers, dual svs pb2000 or pb 13 ultras and play 3 surrounds, but most of the time when I pitch along those lines the client says if we are going down that road I may as well go the full hog and get an av amp.
The ability to add multiple subs to get the desired sound would catch some of those customers with a quick and neat install with good looking kit I reckon.