Because modern cars compete with animations that amaze users/buyers.

In either way, it will be open source and quite fun to build stuff on top.

A game engine is sort of just a UI toolkit for interacting with 3d objects. If you want a 3d model you can interact with, you call that a game engine. Should they invent something new because they dislike the word "game"?

Because you need and want all the fancy features such as

  - fancy HDR rendering with reflection planes,atmospheric effects, tone mapping, camera effects, all kinds of animations for doors opening, lights turning on off etc
  - content pipelines to get all this data from digital creation tools into packages deployable on target

The market for automotive features in the US diverged from "need" long ago.

Game engines, UI frameworks, desktop environments, and web browsers all share a lot of features. The Arcan project is my favorite piece of software running with this idea rn

I don't think anyone's seriously using Bevy's 3D renderer, only the ECS. The only successful 3D game made with Bevy so far seems to be Tiny Glade, which used its own renderer.

I'm surprised Toyota even used something as new-ish as Flutter. Carmakers usually are the last to adopt anything.

Bevy is the opposite of an old boring solution. It's a cool engine, but I imagine a manufacturer would like to have long-term support with 15-year timelines. Bevy doesn't offer that, and even trying to have that wouldn't be good for Bevy.