vb compiler?

Why can't VB use a system like C++ for the runtime libraries and such where we Include them into our program? When we run the program from within the compiler, it could still be interpreted with DLL's that contain all these runtime routines. The routines in the DLL's could also be in individual files for us to include and when we compile, only the routines we use in our program would be added. I don't really understand how a compiler works so what I described might sound crazy. Why wouldn't it work? Could someone explain how the compiler works?

The answer to why you can't include the runtime dll's in your program: Microsoft felt like being dumb so they didn't put that feacture in.

yeah, how does a compiler work?
it must parse the code into separate words.. then what?