It might be good to take a step back, and realize that the tool which is most "clear" is almost always the one which the user is most familiar with. It doesn't follow that the "clear" tool is actually more simple or more expressive.
To find out which tool is more simple, we could just count core concepts or use docs-length as a proxy. But 50 years of makefile's will muddy the water here.. is it super complicated or just well-documented? At minimum, when you reach for makefile then you know the concepts it brings are stable if complicated, and the tool is available by default almost everywhere, and the tool-versioning is almost totally safe to ignore. Looking at taskfile, I don't know the schema for the config-yaml, and more importantly I have no real confidence it's stable over time. Worrying about that sort of thing for project libs is enough work, so people don't want this kind of trouble in their build system. I also know taskfile isn't available by default until I install it.
Build-system yak-shaving mostly comes down to the same stuff. A group of people who don't want to learn tools try to convince everyone to learn some different tools, failing to realize that most of us are lazy in the same ways. Don't want to learn makefile tips and tricks? No one does really, but no one cares about taskfile tips and tricks either. Given the basic equivalence between these two situations.. there's definitely some wisdom here in preferring the standard rather than the startup.