I was involved with the KDE project when CMake had just been introduced. The reason for the switch to CMake (which by that time was still quite new) was that the auto*hell had become so messy that only three developers would even dare touch it to add new dependencies or compile flags etc., which is insane for a project the scale of KDE. OTOH, most developers are comfortable doing these things themselves in CMake. That's not to say there aren't parts of CMake that are still only understood by select people (hello cross compilation).