With some distribution projects starting to adapt age verification code, I wonder if people are now starting to realize why immutable filesystems are such a concern? Once a distro bakes user tracking code into the core image it's harder to get rid of it when dealing with an immutable operating system. With a writable filesystem the component can just be swapped out or recompiled.
The immutable O.S. never included a hostile O.S. in the threat model but if it comes to that maybe its better just not to use a hostile distro to begin with?