“The YouTube app disappeared from Fire TV at the beginning of 2018. This was part of the fallout from a feud that began in 2015, when Amazon banned the sale of Google Chromecast devices, including devices by third-party vendors. Amazon’s reason at the time was that Prime Video did not play well on Chromecast and they would only sell devices that could stream Prime Video. But what Amazon didn’t say was it was its own choice to drop Amazon Prime on Chromecast.
Analysts speculated that the fight actually began because of the competition between voice-assisted devices — Amazon Echo versus Google Home. The Alexa-enabled Echo was released in June 2015, Google Home with Google Assistant in May 2016.”