Having the software is not enough. A web browser is not one and done. Without a development team behind it, Firefox would fall even further into obscurity. Also, a failure at Mozilla would send a pretty clear message that the whole idea is untenable.
This idea that Google is pushing too many features is just silly.
The fact of the matter is that the web has been losing to native mobile apps and closed ecosystems. For many people, Facebook's mobile app is the Internet, and they're installing it from a closed app store. The web is an open application platform, whether you like it or not, and it either evolves to compete with mobile apps, or it's going to die.
For this reason, Google does more to preserve the open web than its competition in the browser space. And yes, I find these stats worrying when opened in Firefox:
And look, if you want to use a text-based browser like it's the 90s, go for it, but I'm pretty sure that most people are glad to see apps running in their full-fledged browser; because the browser is cross-platform, it's the perfect sandbox, and opening a web page isn't gated. YMMV.