I'm sure Apple knows Sonos very well, as do other Sonos competitors. No doubt a good percentage of their employees are using Sonos right now. The difference is Apple has way more money and engineering behind them than anyone else. I don't think anyone else has the man power to engineer anything better. If Apple wanted to they could do what Sonos does. So what is stopping them? Patents? Perhaps no one else is as focused as Sonos who does nothing but wireless speakers.