We can't ship Google Apps due to licensing restrictions (and even if we could, a very vocal subset of users probably wouldn't like that), but not upgrading Google Apps (and/or select other addons/components, for that matter) during a major version bump breaks the installation beyond repair.
It's unfortunate that this is the case, but there is no way around telling users to do major version upgrades manually instead of doing it all in-system.
Sadly, they have to be.
We can't ship Google Apps due to licensing restrictions (and even if we could, a very vocal subset of users probably wouldn't like that), but not upgrading Google Apps (and/or select other addons/components, for that matter) during a major version bump breaks the installation beyond repair.
It's unfortunate that this is the case, but there is no way around telling users to do major version upgrades manually instead of doing it all in-system.