Chromecast for TV now runs android, CastOS use cases are mostly moved to android or fuchsia now.
> There were no feature advantages to the Fuchsia transition
I agree, yet I'm glad they did this just for the interestingness of technology. (Theoretically, the Rust based OS may have better security/protection against memory/buffer issues, but thats surely overshadowed by the bug risk of a new OS)
> It would actually be very easy to kill it
My understanding from my time there is that CastOS isn't in a shipping-new-features state anymore.
> If Fuchsia was gone, Android would take over.
This is why the announced Pixel Tablet is also a hub device.
There are still a lot of midrange phones out there, and IOS has always felt smoother.
GP comment mentions that userspace apps on Fuschia are predominantly Flutter apps, which isn't only running Dart (in a VM), but also using Skia for 2D (and 3D?) graphics, and that isn't going to go faster than native. With Fuschia, I believe the primary objective has always been a secure kernel base to build the rest of the OS upon. That is pretty hard to do with Linux without performance costs or support from underlying architectures (ex: https://github.com/google/kernel-sanitizers).
The Android Runtime otoh has long moved to AOT for hot-paths (profile-guided optimization) and JIT for the cold ones.
The biggest difference is that while some Android devices might be a sluggish if too many applications are taking liberties with memory, on iOS they just die, specially on Objective-C code, where not everyone checks all pointer related code.
Surely someone "took responsibility" for that one
But if you mean UI of Android TV itself, then it seems to be a choice of a suitable SoC, or rather not picking an underpowered one. For example, Nvidia picked well for their Shield line.
They initially ran a version of the same "CastOS" (we didn't call it that then) the same as what ran on Chromecast sticks. But the landing screen on it is richer than what boots on a Chromecast, and it had an interactive gesture based touch screen. CastOS is just a Linux distrib with some boot and build stuff stolen from Android, but the user space for it is basically booting straight into a chromium based web shell.
Before it (the display assistant) launched, I wrote (and ported from ChromeOS) some of the gesture stuff on it. And some of the accessibility features (magnification).
The "Dragonglass" UI that ran on it was originally built as a HTML/TypeScript stack application. Later it was rewritten in Flutter/Dart, ran for a while like that on CastOS using a Wayland-based wedge layer; and now it runs on Fuchsia.
(I don't think any of this is particularly internal or secret anymore since it's old news and replaced, and most of it was visible from the public chromium repo. Also they can't fire me anymore because I quit ;-) )
Those devices never used to run Fuchsia, they ran the Chromecast linux distrib. When I left that team half the devices (the small ones) were being re-flashed with Fuchsia, but the big ones were still running Chromecast. The UI layer was the same (Flutter-based) on both and a consumer can't tell the difference. There were no feature advantages to the Fuchsia transition. (In fact the opposite since a bunch of stuff [e.g. accessibility features] had to be rewritten from scratch)
I'm sure some stuff has bitrotted, but last I looked Chromecast was still a thing, so the OS distrib is still there and shipping on devices. And it will still run on those devices in the field.
Not actually suggesting this as a course of action, but I think you're wrong that they have no alternative to keeping Fuchsia. It would actually be very easy to kill it. It was super late rolling out on the Home Hub, added nothing consumers didn't have already, and would not be noticed when it was gone.
Besides there was always a political turf war about those display devices in which certain product teams (with the ear of people higher up) really thought they should be running Android. Unfortunately Android was a pig and couldn't reasonably perform on the bargain-basement SoC that was used. If Fuchsia was gone, Android would take over.