The last 80 years have been exceptionally peaceful compared to the rest of history, so I hope it continues despite America's loss of hegemon status.
After the cold war has ended, the western nations focused on not giving a fuck about military strength, allies or facing opponents the size of Russia or China. Instead some small-time infantry campaigns like Iraq, Syria and Afghanistan were started and then basically abandoned without any decisive result or even with a total failure. But even back in the 2000s, there were no common goals and no real alliances, just some commitments to save face and keep up appearances.
So now, Russia in Ukraine and Iran in the Persian Gulf have called the bluff that is Western military power and decisiveness. I'm guessing those were just the first instances of a long line of wars that should have been prevented by the US-lead West, that are now possible because the West is fractured and aimless.
Of course circumstances, reasons, participants and histories beyond that were different.
WW2 was the direct result of that "historically consistent belligerence". Simplified history: lots of tension in Europe -> WW1 -> screw you Germany, we won -> Hitler: we are not having it! -> Germans: that's the guy we need! -> Oops -> WW2.
That why they did it differently post-WW2, focusing more on international collaboration (and a little indoctrination, you don't want to miss an opportunity do you?).
Also, Europe is not the center of the world anymore, they have better things to do than infighting.
More fault lines and pirates and no one to police them.