You raise a valid point about the practicality of Sonos integrating Fcast support, particularly in relation to the current app ecosystem supporting Fcast. As of my last update, Fcast, being an open-source protocol, has been gaining traction primarily among developers and tech enthusiasts. Fcast has capability to stream audio from various operating systems. This aspect significantly enhances the potential for a wide range of services and applications to utilize Fcast for audio streaming.

Fcast's open-source nature and compatibility across multiple platforms like Linux, Windows, MacOS, and Android, positions it as a highly versatile protocol. This means that it might be possible to stream audio from almost any operating system, broadening the scope of applications and services that can send audio via Fcast. The advantage here is that users are not limited to specific apps that have built-in support for Fcast. Instead, any application running on these operating systems could potentially leverage Fcast for audio streaming.

Regarding your point about Sonos speakers integrating Fcast, this universality of the protocol adds substantial weight to its practicality. If Sonos were to incorporate Fcast support, it would open up a myriad of possibilities for users to stream audio from a diverse array of sources, not just limited to mainstream or popular apps. This could include everything from custom-built media players to specialized audio applications, thereby greatly expanding the utility and appeal of Sonos speakers.

As for the current landscape of apps supporting Fcast, while it might be in its nascent stages, the protocol's flexibility and broad OS compatibility suggest a promising future. Applications like Grayjay, which already utilize Fcast for media streaming, are just the beginning. The open-source community is known for its innovative and rapid development, so we can expect to see a growing list of applications and services adopting Fcast soon.

In summary, the integration of Fcast into Sonos speakers could be a highly strategic move, not just catering to current Fcast-supported applications, but also capitalizing on the protocol's potential to work with a vast array of audio sources across different operating systems. This could position Sonos as a leader in embracing open-source technologies in the audio industry.