IIRC the persian empire or Acheamedic empire as its known for that period occupied an area slightly larger than the Roman Empire did at its full extent, I expect a great many religions were practiced.
I think its an A led to B moment, the knowledge and philosophy that came out of Greece resonated far beyond the weight of its tiny population, also had the Greeks failed I do not see quite where the persians would have stopped expanding within reason, the Greeks were the regional military masters for quite some time along with macedonia until the Romans came of age.
However I do not think bad of the Persians, for at that time they were doing things and reaching peaks no other society had done up to that point in there own right.
I think its more seen as a triumph of reason over madness, Xerxes and his daddy Darius were barbaric leaders to say the least, though at the same time certain Greek societies left a lot to be desired, eg in Sparta where hunting members of the helot class was seen as a valid use of time, the spartans made great soldiers but their ideas about who could and should be called a spartan would lead to there decline, however its worth of note that even Alexander the Great thought it an unworthy reward for the risks going to war with them, not until the Romans arrived were they beat though they did lose certain battles in thier history, by the time Rome arrived only as little as 3000 spartan men were classed as citizens, ie no army big enough to fight Rome and I bet the helot classes welcomed Rome with open arms, Sparta under the Romans became a tourist spot they viewed spartans as a military and society version of how we might see the Amish, the spartans were also recruited by Rome and fought well in Dacia for them.
In Athens a flip side emerged though, although for long lengths of time weak compared to Sparta, the nuts a bolts that emerged from that city influence greatly whats best about today, having said that all the man boy love going on was sick.
Democracy, multiple fields of philosophy and the births of science as we would come to know it and reason, not that they were alone, the also incorparated ideas from elsewhere.
Think its just an if A went differently B might not have happened.
Plus its a tale of sacrifice for the greater good.
