> You are using users in plural.
Because I am talking about people who use Macs in general?
> Macs are not typically used as multi user machines. Certainly not by developers.
There are developers who share Macs: not everyone can afford to have a computer to themself. But that's still beside the point: regardless of the number of humans using the computer, Macs still have multiple permission levels, and there is always a "root" with more permissions than you.
> configure it to install stuff elsewhere
Yeah, this tends to break if you actually try this. Homebrew explicitly tells you that this is not well supported.
> Also, /usr/local is completely empty on a fresh OSX installation and the whole point of homebrew is to have the stuff you install with it on the path.
Yes, but there are better, and more secure ways to do this. What you should be doing is require sudo to install to a directory that is global and automatically on $PATH, or install locally to ~/bin (for example) and then put that on your $PATH. The way Homebrew does it, where it changes the permissions of /usr/local's folders, is bad because it opens the door to attacks when system software running as root picks up binaries from $PATH (which you have now changed ownership and permissions of to be writable by your user) making any code execution bug instantly become a privilege escalation attack. This isn't the first time I've had this discussion, so I have more detailed explanation which links to an actual example of this being exploited in practice: https://saagarjha.com/blog/2019/04/26/thoughts-on-macos-pack...
> The only vulnerability is the single user of the laptop being an idiot.
Aside from the fact that the security hole exists regardless of me doing something stupid, I'd like my software to work as well as possible in the face of me being an idiot ;)