It is almost certain that the old appetites are still there. The big changes are probably that democracies tend to be less expansionist (democracies don't like needless wars, voters die) and that all the countries that aren't the US basically imploded in World War II.

Most of history isn't a great guide for what happens next because of technology changes. Up until "recently" wars were won by logistics, numbers and training. In the modern age, logistics requires a very complicated industrial system capable of producing, eg, nuclear weapons and satellites. So far, only the US has pulled this off and only the EU has come close to (maybe they have managed as well, I don't know).

Life may get more tense when a new challenger to the US emerges. Maybe China.