The geography of those many remote regions (e.g. the interior of Africa or Australia or parts of Asia) meant that they were not really governed by the empires -

The geography of those many remote regions (e.g. the interior of Africa or Australia or parts of Asia) meant that they were not really governed by the empires - it's just that they were linked to the wider world through various port cities, and those were generally governed by some empire and within a month of its capital, so the value of their trade was captured tehre.