We have done several threads about the most ASBish events of OTL. Personally, I think it all depends on when you stand. If you are in the VII century, Europe's ascent (and decline) might look absolutely ASBish. Not so much if you are standing in 1750. The same thing happens with the British Empire.
But that's not what I would like to talk about in this thread. What I'd like to know is what are those event that should have happened IOTL, but didn't happen (and whose absence IOTL would be considered ASBish from the point of view of observers from any ATL)
I think one example of this is the fact theat, in 200 years, there has been no war between Argentina and Chile. Both countries share one of the largest frontiers in the war. Chile has fought wars between Perú and Bolivia, and Argentina has fought agianst Brazil (1825-28), Bolivia (1836) and Paraguay (1865-1870).
And yet, even if both countries have had, ocasionaly, very tense relations, and they almost went to war several times (1870ies, 1880, 1900, 1978, 1982) there was never a war between both nations.
Can you think of other examles?