One reason against the CMakeLists.txt at the root: When you generate a Visual Studio "solution", every target becomes a "project". At work this results in a few

One reason against the CMakeLists.txt at the root: When you generate a Visual Studio "solution", every target becomes a "project". At work this results in a few hundred projects and VS gets slow. Someone build a Python script to trim it down. This is treating symptoms instead of root causes and adds accidental complexity. Of course, the root CMake also needs to parse all sub directories which requires time. However, this has not been a big problem in practice so far. Only on the "annoying" level.