As I remember, the terms macro and micro photography go back to the days of film cameras. If the close up photographed image of a subject was, on film, the same size as, or smaller than the actual image itself, then it was called macro photography. In other words, if you took a close up image of an ant and the image size on film was the same size as the ant or smaller than the ant then it was referred to as macro photography.
If, on the other hand, you took a close up picture of a grain of sand and the lens in use rendered an image size on film that was larger than the actual subject, then it was called micro photography.
Do I remember this correctly? Don't know how these terms might relate to macro and micro economics.