It's disappointing that we are in the situation where we have several competing protocols for streaming audio - Google Cast, AirPlay, Spotify Connect, UPnP/DLNA.
As a society we are capable of making software and hardware that interoperate among manufacturers - email and HTTP are good examples. We could be a far more technologically advanced world if capitalism didn't encourage companies to create competing closed-source protocols that only benefit the companies themselves, to the detriment of everyone else.