One can only hope that more will eventually find its way into Linux, like with how paid employees at Google have been spending the past ~6 months cloning mimmutable (which HN characters decried as "useless") to make mseal() for defending Chrome.
Really? And how many systems have made any effort to use it, on OpenBSD most of a programs static address space is now automatically immutable (main program .text, ld.so .text, .bss, main stack, dymamically-loaded shared libraries, and dlopen()'d libraries mapped w/ RTLD_NODELETE.
Nobody else have done the work on a complete operating system.
You're basically going "nobody else did this properly" because others did a different implementation. In other operating systems at least they go "oh we saw a chain that targeted xyz structure in this page and modified it so we are going to make sure it is really immutable". How did OpenBSD arrive at the conclusion that what other people are doing doesn't actually confer the full security benefit?