Damn, you know a lot!
Thanks! Like the Romans, the Persians used conquered peoples as a recruiting pool, and used the foreign troops in other conquered places where they'd be unable to join forces with the locals. Also, given the size the empire, it wouldn't have been possible to do it in any other way. When the Persians lost (and they had some real ugly losses) they, like the Romans, didn't collapse, but rebuilt.
After Salamis, the Athenian Themistocles, who'd convinced the Athenians to build their navy in the first place, was ostracized / exiled from Athens, and took a job as the able city administrator of one of the Persian-ruled Greek cities of Anatolia.
Overall, in Greece, the Persians got their asses handed to them, but used cash and skill to keep the Greeks from uniting against them, even to the point where they paid the Spartans' cost of building a navy to compete with the naval supremacy of Athens during the Peloponnesian War, leading to the defeat of Athens.
By that time Sparta had exhausted itself, and was comprehensively defeated by the Thebans, who systematically destroyed the slave-based economy of Sparta by freeing the long-occupied non-Spartan neighbors in the Peloponnese.