The cost of governance

History has taught us that the more the lands, resources and trade routes a regime controls the richer the state is. Wars traditionally were a very profitable empire bringing loot and access to resources which could fill the state’s coffers for ages. All this was true till about the early 20th century (First World War to be precise). I wonder what has happened since because today:
1. The richer and more advanced the country is, the more debt laden it is. Poor and developing countries are bailing out the rich, while the rich are unable to muster enough currency to every pay the interest on these debts.
2. It does not matter who wins the war, the participating nations are never able to recover its cost. I might be wrong but the reason why there are so few wars in recent history is because no country thinks they can afford one.
The question is till how long will China & Africa continue to fund the prolerific
Update: Right from the ancient time to Great War (world war 1, 1914), the army was under Ministry of War. People never talked about percentage of GDP that was being spend on army, navy or airforce. Instead each army was like a business enterprise. The loot & plunder or protection taxes always exceeded the expense to train & equip an army. Also after a elongated long conquest, the army general usually paid tribute to the emperor (often as Spanish Steps, Colosseum and glorious building). As mentioned in this post, only in the recent time has the defense being shown as a cost center.