People can really easily abuse the Makefile ecosystem and write complicated, difficult to read, spaghetti builds. If something fails somewhere in the m4 macro forest while building on your specific machine, you're hosed for potentially hours or days while trying to figure it out so you can just build the damn project. The whole point of this kind of tooling should be to take some of the heavy lifting out of getting source code built, not add extra complexity to a project.

I've been working on and off with Make, C, autoconf, etc for ten years. Maybe if I were a full-time C or C++ person I'd have less trouble with this, but it seems rather excessive. The thing that most discourages me from contributing to certain open source projects is when I clone the repository and the build fails and I can't get the project to build in an hour or less of build-debugging time (and I'm not on a weird setup, I'm on a modern Lenovo with Debian).