That's for GNU make, not POSIX make [1]. For some people, they either won't, or can't, use GNU make.

[1] https://pubs.opengroup.org/onlinepubs/9799919799/utilities/m...

Who even implements an alternative implementation to GNU make? FWIW, no one "can't" use GNU make... even Apple uses GNU make (hell: they even ship GNU make, lol).

BSD Make exists. Also, are you saying that no one is developing software under a contract where they aren't allowed to install software on the target machine? I'm also unsure whether GNU Make works on embedded systems.