The vast, vast majority of people have no idea what E2EE is or what it implies for data recovery.
Making ADP the default would just lead to millions of angry Apple users who constantly need their account passwords reset permanently losing data. This would be a very bad move for Apple.
Privacy is a right, but it takes personal responsibility to actually implement. If people can’t be bothered to learn about the basics then it’s on them when something bad happens because of their laziness.