If they can be private indefinitely, then you wouldn't need to keep them secret.
These attacks on freedom will continue until every computing device is mandated to have an ML system tracking your every input. And no communication method is safe from that.
Not even steganography would save you because more and more people would do it and they'd make it illegal too.
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EDIT: Technology can give us tools to fight it but this has to be defeated at the political level, likely by enshrining privacy is a core human right.
> until every computing device is mandated to have an ML system tracking your every input
Well, in that case yeah, that would suck. OTR, OMEMO, etc. would not help then. Collectively not buying new hardware and pushing against it collectively might.