> Were the Greeks that original in some definite way that later stuff is derivative but they aren't?

I believe some folks are interested in if Indian thought and philosophy, or other Asian philosophies / schools of thought had any influence on Ancient Greek thought, as there was communication, trade, Alexander the Great conquering stuff, etc. But I believe it's an open question and probably one difficult to answer.

Schopenhaur, Nietzsche, and others, were aware of and admirers of Buddhism.

https://en.wikipedia.org/wiki/Buddhism_and_Western_philosoph...

IMHO there's generally more cross-pollination, in multiple directions, than is generally realized or credited.