The simple answer is it varies hugely depending on WHERE in those locales you are talking about. For example, take Asia -- prices are radically different in Kuala Lumpur than in Hong Kong.

I think you're going to need to be more specific rather than just name entire continents, although very possibly someone else has better info than I do.

If you are just looking for the cheapest luxury hotels which are not in a war zone, I would guess they would be found in the lower-cost countries in Asia, of the three areas you mention.