I don't know if it justifies the "billion" that the other commenter threw out there, but there are a ton of Airport Express wifi devices, which support Airtunes. That's obviously not exactly the same thing, but saying that there are only 0.4 billion devices instead of 1 billion doesn't seem like a particularly strong argument.
Can you clarify how you think needing a separate Android device to control a Q to stream to a TV is the same as needing an Apple TV to stream to a TV? An Apple TV comes with a basic remote, so you don't need anything other than what comes in the box to actually use the device.