Breadth of support and retention of historical support are also priorities that differ between other software distributions, especially free operating systems.

See Debian vs. Ubuntu, or NetBSD vs. DragonflyBSD.

Some software distributions emphasize package freshness and coverage, like Homebrew does, which multiplies the support burden involved for each architecture or platform supported.

Others have a more prominent focus on backwards compatibility or exotic architectures, but have a smaller or slower-moving package set.

That's an excellent question for the maintainers of the MacPorts project! It can supplement the very clear and polite answer you've already received from a maintainer of Homebrew.

Different philosophy of dependency management.

They've never actively disallowed it, and volunteers have been happy to maintain it.