Wars are for poor nations

Only one war that I can recall since WW2 was fought on the land of a rich nation, Israel, and that was very much a special case. There have been no wars on the soils of Japan, a Western European nation, the USA, Canada, Australia, or New Zealand.

Why have poor nations had wars while rich nations did not?

Several factors come to mind. I will list them as thoughts much more than statements of fact:

1. The governments of rich nations have learned that wars almost always produce a great deal of harm and very little good (the USA administration is not concerned about this so long as the harm is in someone else's homeland).
2. Rich nations want to remain rich and getting involved in a war that you might loose is going to set you back against all your competitors.
3. Any administration would have to be completely mad to go to war against a nation with nuclear weapons.
4. If your country has nuclear power stations and your potential enemy has significant air power then you would not want to get involved in a war - think of the damage that would be done by the many thousands of tonnes of highly radioactive material spread about if your nuclear power stations were bombed - it would be like Chernobyl many times over.
5. It must be remembered that it is governments, not nations, that decide to go to war. What the government sees as to its advantage might not be good for the nation. Consider Argentina and the Faklands war. The Argentine military junta headed by Leopold Galtieri decided it would be to their advantage to invade the Falkland Islands, a British teritory. Prime Minister Margaret Thatcher of Britain found it to be to her advantage to chase the Argentines out. (Britain is a rich nation, but Thatcher was no doubt confident that this war would not be fought in, or near, Britain.)
6. A war which you might loose is a huge gamble. It is a desparate or foolish administration (not to mention an unethical administration) that starts a war that it might loose.

The 'War against Terrorism' is not a real war. The USA and Australian administrations find it a convenient way to keep their citizens in a state of fear; while their citizens are afraid of an outside threat they are less concerned about mal-administration at home. More pedestrians are killed crossing the road every year in the USA than were killed in the Twin Towers attack; have we heard George W Bush declare a war on unnecessary pedestrian deaths?

Wars could easily be abolished if the wealthy nations had any will to do so.