I think Philip I of Macedon did a pretty good job of dividing the city-states prior to military operations while Xerxes did a pretty good job of uniting them.
Agree with your other observations, btw!
Common idea but mistaken.
The considerable majority of continental Greek states medized, notably including Thebes, one of the great powers of the Greek world, Macedonia, the Thessalians, etc. Many Greeks fought on the other side at Salamis, for instance, though quite possibly with no great enthusiasm.
The Persians were not Assyrians, and were by comparison to other great empires remarkably tolerant and allowed their subject peoples significant freedom.
Given how the Greeks tore their world apart in civil war not too long after, it is possible to make a good case they would have been better off, materially at least, had they submitted to the Pax Persiana.