Google could have taken firefox and improve it to make it better, but they created something new.

Now instead of improving the linux stack and the gnu stack (the kernel, wayland, the buses, the drivers), they rewrite everything.

They put millions into this. Imagine what could have been done with it on existing software.

They say they are good citizen in the FOSS world, but eventually they just use the label to promote their product. They don't want free software, they want their software, that they control, and let you freely work on it.