You might like to see: Weren't there any philosophers from Africa, America or the Middle East before Socrates? on why Socrates broke with previous wisdom traditions in defining philosophy, and why as such other traditions are inevitably going to fit imperfectly into this Western category defined within a specific discourse.
Buddhist thought involves some very sophisticated ideas. Like Indra's Net, which we can relate to modern ideas like a peer-to-peer picture of reality. It's seriously thought acceptance of zero in mathematics was underpinned by Buddhist ideas. India developed it's own school of logic, called Nyaya. And Nagarjuna developed the catuskoti or tetralemma, which allows a more flexible approach to understanding things like fictions, sratements about events which may or may not happen in the future, and even an avenue of approach to how humans avoid the halting problem but binary logic does not. Paper was developed by Buddhists, who made the worlds oldest printed book, a copy of the Diamond Sutra.
The Arthashastra was only recently rediscovered, but is a profound work of political philosophy and advice to rulers on statecraft.
China formed a far more cohesive and continuous political structure than any other region, and this has to be attributed to Confucianism. The Han dynasty which upheld it, was able to develop continuity that the Qin failed at. Discussed here: Why is Confucianism considered a brilliant philosophical school of thought?
Looking at philosophy as defined by 'ground breaking results' is a mistake. Philosophy is about gaining your own personal toolbox for your own problems, rather than having a set of truths to be carved in stone and beaten into the head of every student. See (Why) is this negative outlook on the concept of philosophy misguided?
I'd make the case that far more important than any specific Ancient Greek 'breakthrough', was Socratic Dialogue being fused with Pythagorean math-mysticism by Plato in creating his Academy and so academia, and then Aristotle's Lyceum having the ambition of universal education which led to the idea of universities. Having Alexander The Great as your student with a stake in bigging these thinkers up really helped. The mechanics of who paid for books, libraries, text memorisation and chanting, and the time of monks and professional teachers, has had an enormous impact in what we know about the past in different places, abd what texts reach us now. It's reckoned we don't have any of Aristotle's own writings, only the lecture-notes of his students. Imagine what is lost that was in the Great Library of Nalanda.
