Why surrendering the high ground compounds a tactical mistake

In two battles, the computer opponent fails to occupy the crest of a hill. The first error lets Carthaginian cavalry begin above the Roman formation. The later mistake is worse because even the slower Carthaginian infantry reaches the higher position after starting lower down. That elevation gives both arms a stronger starting position and leaves the enemy approaching on less favorable terms. These are game examples rather than reconstructions of specific ancient battles, but they make battlefield terrain and positional foresight visible.