There is no doubt the political structure was supportive. Greek democracies promoted free thought and equality among the people. Still, there had to exist the intellectual capacity and curiosity to produce advanced thinking. There is no question that the Greek art, architecture, and philosophy still have great influence.
Separately, mathematics and science continue to advance today as they have continuously over two thousand years – how could they not given the number of thinkers, perhaps more in one American university today than all of Greece in 450 B.C.