This is not an apples to apples comparison. I've given examples from runtime, not from development time.
OTOH, refactoring in C++ is not hard, at least from my experience. With some knowledge of the language, everyone can write reasonably bug-free C++ (or any other language) application in one go.
Compilation in C++ is a different story. C# is not native. It's converted to CLI (was that the name, I don't use Win32 for ~15 years), then JIT compiles it to machine code, and optimizes over and over in every execution.
Yes, C# is reasonably fast, but it's not native, cross platform (mono doesn't count), and designed to be a systems programming language.
People tend to think C++ is overly verbose, no. Win32 programming model forces simple operations to be long and time consuming for a programmer to implement. Opening a file, serial port, or anything is a single line, because of the (while not everyone likes it) "everything is a file" philosophy, which makes UNIX and C++ much easier, verbose, and accessible.