>>17929924
Persia already controlled a lot of the Hellenes for 30 years by the time of the Battle of Plateau and had already returned a lot of the city-states Democracies. Sparta got involved to give freedom to the Ionian Greeks supposably, but they were already returned to autonomous Democracies under the Achaemenid Empire. If Persians had won the Greco-Persian Wars, it wasn't going to erase the Hellenes.

In fact the Classical Age of Greece, the famous period of scientific growth and wealth, happened because Hellenes was introduced into the Persian trade sphere which gave the Greeks access to Babylonian and Egyptian science. When all the Greek writers talk about Chaldean texts in their references they're talking about Babylonians. The Greek city states learned systems of administration under Achaemenid rule which allowed them to get their first professional armies - which the Macedonians would eventually use to conquer Persia generations later after Persia descends into a 100 year civil war rotting it from the inside out. The idea that the Persians were going to eradicate the Hellenes or Democracy is a modern one because some people wanted to turn this war into a story about defense of Europe.