What prevented the lapita, polynesians, and others from developing an empire in oceania and nearby regions of the world?

Geography and political organization.

Explanation:

The Lapita culture settled in many of the islands of Polynesia establishing villages with no other intention than farming, breeding and living  based on their culture. They never organized under the concept of settig a more organized and bigger order like a captial or state-city, in fact they were sea explores looking for opportunities to live accross the Polynesia, but never as conquerors as they never built military forces to consider being a threat for other civilizations. The geography of Polynesia was not very fit for the purpose of setting empires. Maybe if the Lapitas had established in Australia, things would have been different, but  the chose small islands which was also a limitating factor for them to grown as an empire.

explanation:

japan participated in world war i from 1914 to 1918 in an alliance with entente powers and played an important role in securing the sea lanes in the west pacific and indian oceans against the imperial german navy as the member of the allies.

he supported the seperation of church and state. he also promoted religious tolerance.