When/if Google ditches Android you think they will give up the echo system? You think suddenly Android apps wouldn't run on Fuchsia? It would be a seamless transition(look at how they did it on the Nest Hub).

All the "cool" new Google features and performance upgrades may be Fuchsia only. I wouldn't bank much on Amazon. They just need an OS to run their readily disposable devices. I don't see them putting too much effort into this.

Google is going the hold the hand of manufacturers and ease them into it.

At least if Google had any sense this is how it would be done.