Regarding the number of options, C++ has quite a few IDEs: Visual Studio, Xcode, VSCode, CLion, and probably more (Oracle probably still sells the one they had for Solaris). For command-line compilers, C++ has: Visual Studio, Xcode, g++, clang++, IBM C++ compilers for their OSs, Oracle compilers for Solaris, etc.
For Ada, is there anything other than AdaCore? Is that the same as GNATStudio?
Edit* - fixed Ada capitalization