My understanding is that other languages that don't have this separation of compiling objects and linking them together, can't do incremental builds, and are generally quite slow to build.
C++ is infamously slow to build. I've seen the results of profiling Clang (known as a particularly fast C++ compiler) and the preprocessor takes a big chunk of time. C compiles a fair bit faster.
Try out the Mono compiler for C# some time. It is so fast that you might as well recompile your entire project every time you change one line of code. I'd pay serious money to get that kind of performance from a C++ compiler. Tons of other compilers are really fast. JIT is fast all modern browsers. Go compiles in a snap. Python starts running immediately.
The only other language I use with a compile time comparable to C++ is Haskell.
