Was bevy considered?

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.

Tech is becoming front and center to car sales. Adopting newer technologies is probably seen as a necessary risk to stay competitive.

Bevy releases have a lot of breaking changes, and so do many of the 3rd party plugins.