Maritime mercantile civilizations

I'm asking this in part for an ASB conworld, but it's meant to be firmly grounded in OTL's history of maritime civilizations: the Phoenicians, the late medieval Europeans, Swahili Coast, the Malays. What I'm interested in is why there wasn't much exploration coming out of the Swahilis and Malays. Is it that the Swahilis did not need to explore, because traders came to them from both land and sea? If so, did something similar happen to the Malays - Chinese, Indian, and Arab traders came to them, so there was no need to launch their own ocean-going ships and trade with China and the Middle East?
 
The Polynesians basically spread out across the South Pacific. Maybe if you can keep a more substantial contact between them and the Malays?
 
Yeah, the Swahili thing is simple. Africans came to them, so no point to inland exploration. As for the Indian Ocean, they already knew the whole place quite well (the Song even received envoys from the area) - and why go to the Atlantic where there's no money to be made?

Interestingly, contrary to what many on this forum believe, it took a centralized power over the coastline to achieve the exploration into the inland that the fragmented Swahili states never did. Competition clearly does not always bring progress.
 
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