Now being from 2017 ;)
I suspect no-one has touched that file properly since then because of old scars :(
Part of the issue is there's not a lot of differentiation between most of the "project management" tools (apart from their age, which in some cases explains certain design choices), and the coupling of most of these to their PEP 517 backend doesn't help. There are backends where there is differentiation, such scikit-build, meson-python/mesonpy and enscons for wiring into pre-existing general purpose build systems (cmake, meson and scons respectively), maturin for rust, and flit-core as a bootstrapper, but given setuptools can be used without a setup.py now, I'm not clear on what some of the others provide.
Part of the issue is there's not a lot of differentiation between most of the "project management" tools (apart from their age, which in some cases explains certain design choices), and the coupling of most of these to their PEP 517 backend doesn't help. There are backends where there is differentiation, such scikit-build, meson-python/mesonpy and enscons for wiring into pre-existing general purpose build systems (cmake, meson and scons respectively), maturin for rust, and flit-core as a bootstrapper, but given setuptools can be used without a setup.py now, I'm not clear on what some of the others provide.