I’m thinking about the loss to literature. There probably would never have been the Athenian tragedians, since Persia had a particular beef with Athens. No Xenophon, because those events likely wouldn’t have happened in a less-troubled Persian empire. Could we have even lost Homer’s epics?
Probably not. Greek culture was profoundly influential in Rome, and might have been equally so if the Greeks had been defeated by Persia. Maybe we’d see many differences in the details of what we know as Mediterranean history, but not in the larger sweep.
you bring up a very good point. There would have been no democracy in the way we know it and probably no drama plays etc. in the way we know it. Though it would have had far more repercussions across the world, not just Mediterranean history imho