As a way to prevent the major annoyances of browser segmentation and older versions. This way the code would only need to be done for the latest version of the browser, but users could still have the functionality of the older version and not be forced to do major updates?

I am sure there will be some major flaws in this, and I would like you to tell me what they are!
-Obviously, people may not want this as often auto-updating is frowned upon, however Chrome does it (or at least, they used to);

Without a manual check, Chrome will update itself automatically, Google said. "Google Chrome will automatically checks for updates approximately every five hours. If an update is available, it will be downloaded and applied at the next browser restart," Google said.

-there is still the problem of getting users from the really old ones onto the any new browsers that have this functionality
-To prevent exploits in terms of updates, maybe they could have a 7 day opt-in period before being pushed out to everyone?