True e2e makes it hard to sync a new device and makes it easy to lose all your history. The company also can't help you recover your messages and it's unclear for normal people why (often met with anger or disappointment).

Unencrypted messaging is easier and more convenient, just login from anywhere and done. So there are actual technical and rational reasons to choose against e2e.

> I do not think any person would freely choose unencrypted messaging.

Many people do, e.g. by switching from Whatsapp to Telegram.

The market is working alright; people are (uninformedly) voting with their wallets (or rather, their personal data).

I have so many problems with using Matrix with multiple devices and most of them are caused by its encryption. If there was a magic wand that would add encryption to a system without changing anything else there would be no reason not to use it, but the reality is that E2EE does place limits on the overall functionality of the system.

This is why Telegram and Discord are so popular. They are popular because they work well, and part of the reason they work well is not bothering with E2EE. For instance, when you join a group chat, the server can just send you the message history (if enabled) and there's no need to negotiate keys with every other participant. There no "joining...", there is no "message will appear shortly...", you just press the button and you're in.

I've never seen an E2EE group chat that could remain stable with more than a few hundred participants. Even Matrix gives up and just makes it unencrypted at that point.

This is not correct. People are happy to give up privacy in exchange for the convenience of being able to restore message history remotely, even if they lose their key.