I kept looking for good ways to solve my problem of yesterday. One idea which came to mind was editing /etc/profile to be better behaved with regards to leaving my changes to the PATH alone, but I expected that my changes would be lost every time I installed a new version of Mac OS, so I didn’t try it.
But then Apple released Mac OS 13.5 with significant security fixes, and I needed to install it. I changed /etc/profile before doing the installation, and I was delighted to find my changes were still there after the update, so that may be a viable strategy.
I also looked at my Ubuntu systems to see what they did in /etc/profile – they’re even more brutal than Mac OS. Mac OS puts its preferred directories at the front of the PATH so they’re seen before whatever was in the PATH when /etc/profile is read; Ubuntu simply overwrites the PATH with its own version.
Oh, well; who said using a computer would be easy?