Just to be clear, do you think that the NYT is mistaken, or that Facebook has committed to something that is too difficult to execute due to technical and revenue concerns?
I don't think they committed to anything. It's just vague promises that can be reinterpreted in many ways, most of which can compromise trustworthy e2e encryption while also implementing some form of loophole-ridden e2e encryption.
Yeah, WhatsApp is e2e encrypted by default, but it also automatically backs up all your chat history encrypted using a WhatsApp-owned private key. Sure, you can opt-out of backups, but will your peers do as well? Without a clear spec, I think it's perfectly reasonable to be very skeptical of what will be the final product of this operation.