https://arstechnica.com/gadgets/2019/01/google-kills-the-chromecast-audio/

Another day, another dead Google product. Today, Google is discontinuing the Chromecast Audio. The company told Android Police it has stopped manufacturing the audio-only version of the Chromecast, so when the current stock runs out, the product will presumably be gone forever. Here is the full statement given to Android Police:

Our product portfolio continues to evolve, and now we have a variety of products for users to enjoy audio. We have therefore stopped manufacturing our Chromecast Audio products. We will continue to offer assistance for Chromecast Audio devices, so users can continue to enjoy their music, podcasts and more.