Having seen multiple leading messaging/VoIP stacks from inside, the amount of engineering spent to work around various limitations of E2EE in real prod scenarios is insane, and even for simple every-day-use features metrics don't compare to the metrics of the same feature running without E2EE.
It may just be that ROI doesn't make sense: very few user out there truly care about (or even understand) E2EE, for quite some users it creates an inconvenience & support incidents (harder to move from device to device, forgot your passphrase - lost your history, new joiners to a group chat don't see previous history, etc), it requires a significant additional engineering effort to just maintain it, many new features get shipped much slower because of it...
Just give people some benefit of doubt. There're much simpler ways to explain certain things that suspecting some universal evil in every move...
They’re a bit of a self fulfilling prophecy for why it is a futile effort for trying to secure information near them.