Google is still pushing updates to the Nexus One and Nexus S, so it's not like it's the past.

By the way what I'm talking about is a limitation of Android itself: it has no package management system (with dependencies, upgrade etc.) for core components. And what I'm proposing would allow certain parts of the system to be upgraded while carrier junk stays there.

Google is actually already doing that for Gmail, Market, Music, Maps and other apps. Why not the browser ? (even if for now it uses a separate libwebkit)