There is third party control for SONOS - at least to anyone who wants to devote the time and effort to doing it. Nevo works pretty good, but is missing some key features (mostly queue related) and Pronto is slow. However I offer both products to my clients and they find it good enough.

It's not so bad that SONOS doesnt work with most control solutions - what is bad is explaining this to a client why he has to use two different controllers. I have a Nevo S70 in my office and STLL use my Sonos controller. Besides having all the features, its just a better user experience and much faster so I agree with SONOS to an extent. I am a SONOS dealer and the user experience is essential to the product. But I wouldnt blame SONOS entirely for the lack of support. I have heard excuses from control companies from "it's too hard" to "SONOS didn't say we could do it so we don't want to crack it". Last, I completely agree with what others have said about creating competition. There are plenty of engineers out there - engineer a product that works as well as SONOS with third party control and you have something there...