The standard of living might have improved for the descendants of those that survived but what about those who had to undergo generations of subjugation or slavery or worse? What about those wiped out? In other words at what cost was this long term improvement gained?

Are the Aborigines or US native indians actually better off?

For me the benefits of British rule are very mixed and to argue that the conquered are better off ignores the costs borne in the past. Additionally, we cannot say how things might have been if people had been allowed to develop naturally and trade under normal circumstances.