No, what I mean is that our browsers are becoming OSes. So why don't OSes become more like browsers? The way it works now is that each of my tabs have their own VM (tabs) that runs on another VM (browsers) which itself runs on another VM (OS). Why can't tabs just be processes that run directly on the OS (with all its security features).

Every time I see any problems/advancements in browsers, I squint my eyes and they look exactly like an OS problems/advancements.