Google has said the same thing for tons of things, and then stop caring for them and supporting them.
Including Dart as a JS alternative, the very same technology now relegated to Flutter backend.
I would think long and hard before betting my company on any Google product.
Are there many third-party contributors to flutter? If so, that would make me feel a little more confident. If it's all (or almost all) Google staff, yeah... no. Wouldn't go there.
https://ubuntu.com/blog/flutter-and-ubuntu-so-far
tidbit - there is early support to build linux flutter apps on the raspberry pi. Would be good if android team offered arm builds of their tools, then it would be possible to build for android on the pi.