How long has the world gone without a large scale war after decades of countries building up MASSIVE militaries?
I would like to think a lot longer.
But Russia, Nk and Iran (because of their nukes), China, the US, India, Pakistan (they have em too) and others all have one situation or another that is close to boiling point.
It is what it is i guess.
The general trend in 1st and 2nd world countries is toward smaller, professional armed forces. These are incredibly expensive and also lethal. If you measure the amount of GDP thrown into military spending that is also pretty low for most European countries (What Trump complains about).
As to the frequency of global wars or “World Wars”... they seem to happen every 100 years or so. The last one could be viewed as a double-war (WW1 & WW2) which started in 1914. The one prior to that... the Napoleonic Wars... finally ended in 1815. So you could argue we are “in the zone”.