They have, it's called Macports. It started as a port to Darwin of the existing *BSD ports and (I believe) is subsidized by Apple.
It installs itself in /opt/local, it respects the Apple SIP.
Homebrew basically sucks, because it doesn't follow Unix conventions and it doesn't follow MacOS conventions.
Macports has both pre-compiled and build-from-source, supports current and past MacOS releases, uses xcode/clang for compilation, supports port variants and multiple versions installed in parallel (with "port select" to choose a default) etc etc.
It installs itself in /opt/local, it respects the Apple SIP.
Homebrew basically sucks, because it doesn't follow Unix conventions and it doesn't follow MacOS conventions.
Macports has both pre-compiled and build-from-source, supports current and past MacOS releases, uses xcode/clang for compilation, supports port variants and multiple versions installed in parallel (with "port select" to choose a default) etc etc.
Not sure why people use anything else.