I'm just wondering why upgrading Umbraco is not something that can be done from within Umbraco itself. If a user/admin interface upgrade is not possible then why default to nag users upgrades are available?

Is their a discussion on this somewhere (I can't find one). To me it seems a very bad thing that sites will age and not easily update over time, possibly allowing vulnerabilities to be leveraged against sites. This would also reduce the footprint or increase the work for target-able versions when developing plugins. I'm not a fan of wordpress but this is one area it walks all over Umbraco.