MFC is an object oriented library it stands for Microsoft Foundation Classes, Delphi uses it's own object oriented library "VLC" which stands for Visual Component Library, it's far more sophisticated than MFC and now delphi is focusing on a vector based library called Firemonkey that is used for cross platform development on Android and IOS.

The problem is not in the language or in the libraries; it's in the code efficiency and baggage. You can easily port Delphi to C++, since they are basically the same language aside from the syntax, but all you'll end up with is the same exact program running with code compiled from C++ instead of Object Pascal. Band In the Box was written back in the DOS days and ported to Windows, but for all intensive purposes it still operates like a DOS program. It reminds me of the earlier versions of AutoCad for Windows before they rewrote it to function like a windows program. One thing that would speed it up is to lose all of the unnecessary bitmaps and 3D bevels on the buttons and controls that not only eat up resources but make it look like a program out of the 1990s