Why were the Greeks and the Egyptians the only people who successfully

I'm pretty sure on one rare occasion the Egyptians beat the Persians, the Persian emperor asked who the Egyptian soldiers were, and they turned out to be Greek mercenaries.

Mercenaries are often the outliers in any case, career soldiers, it doesn't necessarily speak to any inherent Greek mastery of ware.

>>2412617
>Were they particularly superior as soldiers?
I'd say it has more to do with incompetence of leadership.

Cyrus the Great had no problem dealing with hoplites during his war against the Lydian empire while being heavily outnumbered. But he actually fought in the frontlines like most Greek kings did and relied on generals. And his son Cambysses II did the same in his conquest of Egypt.

But after that they became lazy and seemed to play it like a game at the expense of their soldiers.
Hell, half of Xerxes expedition force starved to death IIRC.

>>2412651
To be fair, it's disputed as to whether Xerxes even cared that much about Greece as the Greeks themselves state he did. There is a pretty solid theory that Xerxes burning Athens was just part of the right of passage that he needed to do to secure legitimacy in the eyes of the Persian political elite, and then afterward he didn't really care about Greece one way or the other and just left it up to his less competent generals to clean up the scraps as they saw fit.