Everyone is hypothesizing government backdoors and whatever else but to me there's a simpler and more obvious reason - AI.

Companies started pushing E2EE a few years ago because users' private messaging data used to be a liability. Now that the data can be fed into LLMs for training and inference its value has gone up significantly, and the privacy and security tradeoffs are suddenly worthwhile.

PMs across the industry are pushing product decks with "conversational AI assistants" to get their next promotion. I've been in more than one of these meetings myself. If the data is encrypted then there's no way to build this kind of stuff.