alt Hacker NewsThis is based on a faulty understanding of the underlying systems. The risk with this sort of E2E encryption is not that the service provider pinky promises not to decrypt what they have, it's that they promise they will not insert a new key into your circle of trust to subsequently start decrypting things.
I think you've imagined this faulty understanding. There are many mechanisms by which Apple could actually decrypt the data despite pinky promises not to. You listed one. There are others.