CMake suffers from a lack of conventions. If you want to follow some set of conventions and have one directory for your headers and another for your sources and another for your tests etc you still end up having to write a hundred lines or more of error-proned CMake.

As ugly as things like Maven and Gradle are, if you follow all of their conventions they get out of your way.

In addition:

- no cross-platform way to require a compiler version or way to set compiler flags

- linkers are not abstracted from you (good luck trying to get cross-platform support for relocatable binaries; cmake really bungles up rpath etc)

- also good luck trying to link both static and dynamic libraries and targets

- third-party libraries aren't really a first-class thing

- no simple way to specify "build all these things into the target directory with a conventional file layout"

80% of projects need to deal with these and not a lot else. Why is there not a list of "follow these conventions and you don't really need to write or look at cmake file"?

(To be fair: compilers, linkers, and OSes share some blame in not being more consistent but the goal of a competent build-system is to handle these things for the 80% case.)

It doesn't really matter how terrible the syntax and internal implementation are if most reasonable use-cases don't need to look at it.