Software get updated all the time. Users / devs might need or want versions other than that provided by Apple. Including a specific version of software in an OS exposes users to its security vulnerabilities, even if they don’t need that software or that version of it. It provides ample opportunities for version conflicts if someone wants to use a different version than the built in. It also bloats the distribution size. Apple won’t (& shouldn’t) release a new OS every time se third-party software is updated. But users might want to upgrade themselves. Even if Apple did update macOS with every new third-party software version, changing the version of languages / frameworks all the time would frequently break programs that relied on them. Apple might also object to new licenses in newer versions of a distribution, like how they keep providing an ancient version of bash. Please stop embarrassing yourself with your uninformed posts on this topic. If you want to install software, and to either pin it to a specific version or to easily get the newest, use one of the many software managers out there.

The rationale for removing it is that people should be able to choose what to install (or not install) on their system to reduce version conflicts and to remove security flaws, as well as to have a smaller OS footprint. Users should be able to select the version(s) they prefer. Embedding a specific version in the OS exposes users to all the security issues of that version.