Maybe, but it is not because we tend to be overly pessimistic in general, that serious problems cannot happen to us. Entire civilizations have diapered in the past, so we should remain vigilant.
After all, another bias that humans have, is a strong tendency to believe that what is true now, will remain true forever.
I often think about the city-states along the Silk Road: healthy, peaceful, cultured, unprecedented prosperity for their time. All defeated when the hordes of Genghis Kahn rode by, many utterly destroyed
The Empire of Mali. The Kingdom of Lithuania. Macedon. Tyre. Babylon. Carthage. Samarkand. Assyria. All once mighty, all gone, perhaps a place-name remains, if that
For anyone still paying attention, I should have written "The Grand Duchy of Lithuania", which was a powerful state for hundreds of years in the Middle Ages
The Kingdom of Lithuania, while also powerful, lasted about 2 years
Aside from perhaps Macedon and Carthage (indirectly via Rome) most of those don't even warrant a mention in the high school history curriculum (in the US, at least).
The simple fact is that pre-industrial history has had literally thousands of different thriving civilizations around the world. It's simply not possible to even briefly cover anything but a fraction of the more "important" in a non-university setting.
Peace from violent thoughts leading to depression and anxiety which are at all time highs, no.
There were Balkan wars and there were Indian wars, but the vast majority of Western population never served in combat.
And people started thinking that this is how it is going to be forever.
However, I do agree with you that people then thought that world peace was achieved. The 1910 book "The Great Illusion" [2] ironically argued European war was unlikely to start due to the great economic costs of destroying trade between nations. It got the consequences right at least.
[1] https://en.wikipedia.org/wiki/Franco-Prussian_War [2] https://en.wikipedia.org/wiki/The_Great_Illusion
Eh... not really. Anger at the loss of Alsace-Lorraine peaked in the immediate aftermath of the Franco-Prussian War, when France couldn't do anything, but by the 1880s and 1890s, France had resigned itself to the loss. The massive divisions in French society under the Third Republic meant that it was in no position to do anything to reclaim it. A parallel might well be drawn to Finland's position today over Karelia: they'd certainly like it back, but they're not about to fight for it. It wasn't until World War I broke out that restoration of Alsace-Lorraine to French rule really became feasible, and hence it became a major war aim, but it wasn't a factor until after war had already broken out.
The arms race in question is the naval arms race between Britain and Germany, which itself subsided in 1912 because Germany couldn't afford to keep up.