Are there any stats as to the percentage of iPhone users that enable Advanced Data Protection? Defaults matter a lot, and I wouldn't be surprised if that number is (well) below 10%.
If you are the only person out of all the people you correspond with who has ADP enabled, then everyone you correspond with is uploading the plaintext of your messages to Apple.
You have to remember that there are something like a billion+ iOS users out there. 100 million people have not written down their 27 character alphanumeric account recovery key.
If you are the only person out of all the people you correspond with who has ADP enabled, then everyone you correspond with is uploading the plaintext of your messages to Apple.