Personally, I agree about CMake and its horrible scripting language, and I like Scons a lot more. It's Python-based so it's easy to work with and flexible, and not nearly as ugly as CMake.
I think CMake took off, because it has no dependencies, works with any IDE and can be extended to do anything.
I have been in places where demanding python just wouldn't work. Either a specific version was needed for something else and managing the dependencies was a pain or we were already reliant on other scripting languages. I think this kills any other language as a build tool.
There are zealots for every IDE and some IDEs require special project files. If your build system doesn't seamlessly integrate most then it couldn't have made it. Scons never worked with IDEs I liked, Know how to get it cowkring with QtCreator? Other will demand vs2015r3 integration, how do you do that?
Then then there are the build systems you didn't mention, but the minimalistic ones. There was even one that was entirely stateless, but it was also too inflexible for most real builds.
CMake very carefully walked a thin line that dodged all these issues and the fact it is a giant pile of global mutable shared state simply doesn't for all but the largest builds.
