There are some fundamental different between two ecosystems.
On Google, the Google Drive and Photo are encrypted to a key owned by google.
On iCloud, the iCloud Drive and Photo are encrypted to your account key. In which, without ADP, this key is shared with Apple. When ADP is enabled, Apple does not store this key. iCloud Backup is stored with the same technology as iCloud Drive.
When it comes to lost password account recovery:
- Google can just reset your password, and your drive and photo are still accessible. All barrier are procedural, not technical.
- iCloud (with ADP), they can still reset your password, but then your icloud drive and icloud photo are loss forever.
There are some trade off ..:
- Lost password recovery experience. _Some_ user will lost their password anyway. How high should the bar be?
- Cloud first? or local device first with cloud backup?
- Are you giving the cloud data same protection as local device?
In google's solution, they put the google drive data at risk...
In apple's solution, it need extra steps to ensure you have proper account recovery flow covered.