Afaik Chromium is controlled by Google's devs. E.g. Google introduces quasi-standards because they benefit YouTube, without consulting anyone else. It's basically IE again.

You might say ‘just fork it’, but I'll see how you do that and keep maintaining a full-featured browser. That would also make it not a monopoly.

Chromium itself has features tied to Google. The ‘Ungoogled Chromium’ project is dedicated to undoing that.

Likewise Android goes where Google wants it to go.