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 promot…
This does not work. They were initially working on webkit but technical decisions they wanted were different from apple/webkit team so they had to fork. It is much better they implement their technical ideas with their resources.