Wait what? Why prefix length limits? Linux paths can be 4096 bytes long, I can't imagine y'all are hitting that?
Postgres is an example of this: the various directories are set at build time.
It's so annoying how deeply UNIX packaging philosophy assumes that installation directories are something you hard-code at build time.
It makes me think of when Arch merged /usr/bin and sbin with /bin and sbin. Having them split made sense in a ton of scenarios that used to be very common, but increasingly the split was vestigial for most users.
But these days, "early boot" is handled by initramfs and we've all got drives large enough to not need the split anyway.