Well, they sort of have given the option, with WhatsApp. Which has had full e2ee since 2016, using the signal protocol.
Adding default e2ee on messenger is probably a bit trickier, due to the structure (web client, history saved on the server, and so on)
As a bonus, you can just join multiple machines to the cluster and have work spread out over them.
I've pointed it out a few times, but I think it still bears repeating.
Meta have done a lot of open source development, and in that way you're using "meta" products daily. They are the people behind React and GraphQL, for example.
React (and React native, also them) is one of the biggest JavaScript frameworks, and GraphQL is an alternative to REST api's that brings solutions to many problems around REST api's.
I can almost guarantee you that some of the pages you visit in a day use at least one of those.
They also have a lot of other things. You might have heard of pytorch, a major library for developing and running AI projects.
Just have a look at https://github.com/facebook and https://github.com/facebookresearch/
Edit: to clarify, my point is that maybe meta only thinks of itself, but technology wise they do it pretty altruistic and help the related technological communities a lot.
Got some examples? And please, something other than xmpp. That feel apart under it's own weight.
When it comes to open source and open standards, Facebook have done quite a lot. React, react native, llama, graphql, relay, pytorch, docosaurus, zstd, flipper, redux, infer, lexical, jsx and a lot more at https://GitHub.com/facebook
Facebook have already contributed a lot to open source and open standards. Why do you say they won't continue to do that?
Exactly. Linux ended up being a boon for Microsoft. But still people here insist that it must only be for monopoly legality. And that no big company can benefit from and contribute to open source.
So they shifted large parts of azure to Linux, use it internally for many systems, made WSL Linux layer for Windows, spent tons of resources to improve it and support it and made it a first rate development and server system for their solutions like .Net - just so they can say "we're not a monopoly"?
In truth their attempts at EEE failed miserably and hurt them, and Linux is actually a very good match for what they're doing in server space and development space.
You know Facebook has released a ton as open source, right?
Edit: ever heard of React? Facebook. Pytorch? Facebook. GraphQL? Facebook. Llama? Facebook. Plus a ton of more niche stuff. Zstd, relay, fresco, hydra, redex, React native..
Edit2: https://github.com/facebook
I used xmpp, and also Gtalk, both of them. Talking both between xmpp clients and Gtalk users.
XMPP was a mess. Messages often didn't arrive if target was on a different server. And different clients had different encryption and encoding standards, so even if it arrived it wasn't always readable (or just completely ignored by the client). Images seldom worked across different clients.
The only way to make it work reliable was if everyone was on the same server with the same client with the same client version. That is, if the server itself hadn't crashed.
The reason Google stopped the link was because while it had very little of legit messages on the platform, it had most of the spam and trolling. XMPP servers were the "soft underbelly" of Google talk, with the small server admins not having the resources to deal with bad actors even remotely as good as Google.
XMPP was and still is a buggy mess, and the reason Google unlinked it was that while it had a fraction of the legit traffic, it was like 80% of trolling and spam and other crap.
And Google killed xmpp? No, xmpp killed xmpp, if you can kill something that's already dead.
People started using other networks because they got used to
With xmpp messages frequently got lost with no error, different clients having different encryption and encoding settings, different ways to encode and decode media... A complete mess.
People using that as an EEE example are clueless, or stupid.
Also, if meta starts federating, it will eventually stop it for the same reason Google stopped talking with other xmpp servers. Because it'll be the source of most of the crap, but very little legit content.
So you'd end up .. exactly where we are now?
They never should have? Messenger saves the history on the servers, that's how that works. How do you think the fireworks would look if users logged in on a new phone or machine and had no chat history?
There are ways it could be stored encrypted, but if that's a wanted feature they provide WhatsApp
Edit: but this is also why e2ee is so important, and why security experts tell people to use e2ee if possible. At this point, at the top of my head, it's WhatsApp, signal, I think matrix, and sorta telegram that provides.