That's a crypto architecture design choice, MS opted for the user-friendly key escrow option instead of the more secure strong local key - that requires a competent user setting a strong password and saving recovery codes, understanding the disastrous implication of a key loss etc.
Given the abilities of the median MS client, the better choice is not obvious at all, while "protecting from a nation-state adversary" was definitely not one of the goals.
Given the abilities of the median MS client, the better choice is not obvious at all, while "protecting from a nation-state adversary" was definitely not one of the goals.