In general the tooling sucks, which is kind of strange given how relevant COM is on Windows, even moreso since Windows Vista.

It seems the Windows team is against having something like VB 6, Delphi, C++ Builder, .NET Framework, MFC, approaches to COM tooling, just out of principle.

Thus we end up with low level clunky code, with endless calls to specific API like QueryInferface(), manually written boilderplate code, and with the IDL tools, manually merging generated code, because they were not designed to take into account existing code.