Sure, and maybe that's a reasonable position to take commercially, though I note that Apple does use end-to-end encryption for various specific categories of da

Sure, and maybe that's a reasonable position to take commercially, though I note that Apple does use end-to-end encryption for various specific categories of data on iCloud so the argument about being user-friendly with recovery options is not without its weaknesses. In any case, iCloud still isn't fully secure, and Apple isn't very honest about that in its marketing. It also doesn't give those users who do value security and privacy more highly the opportunity to use iCloud with real security, while simultaneously making it unnecessarily difficult to transfer data using other, more secure methods. As one potential alternative for discussion, you could instead construct a system where users had the option of keeping keys entirely under their control, with suitable backup options, or of creating an online emergency recovery system where partial key data was given to Y trusted friends and recovering that data from any X out of those Y would be sufficient to reconstruct the key. Each friend need only know that they are agreeing to be an emergency keyholder for someone, and no-one else other than the original user and the keyholder need know that the relationship even exists. The UI for a system like that could be extremely simple. Turn on the emergency recovery system. Identify a list of friends you want to trust. They each get asked if they're willing to help, and you either get a list of people who all said yes or prompted to choose more people if anyone declined or couldn't be reached. Once you've got enough, everyone who is a trustee carries around a suitable fragment of the other keys on their own secure device(s) in exactly the same way that their own key is held.