The Wikipedia article for Balkan Wars lists it as one of the reasons leading to WW1. Otto von Bismark also quoted
If there is ever another war in Europe, it will come out of some damned silly thing in the Balkans
Is it correct to conclude that the WW1 was essentially an extension of the Balkan Wars?
Not really. It was a war that was bound to happen. It just started in the Balkans. Even that was an accident: yes, archduke Franz Ferdinand was killed, but in the second attempt. During the first attempt Gavril Prinzip was present, but not able to act. Others threw a bomb that bounced of and exploded under the next car. Gavril walked away, and got a sandwich.
In the mean time, Franz Ferdinand was - understandably - furious. He was calmed down and persuaded to continue his visit. His driver had not been informed of the change in route, made a wrong turn and had to back up and reverse. Right in front of the shop where Prinzip got his sandwich. He didn't hesitate for a second, and killed the archduke and his wife.
That was something nobody could have planned.
The war might have begun a lot earlier, for example between England and France over the Fashoda Incident. Or between France - England vs Germany during the Panther Crisis.
It just happened to be the killing of a rather unpopular heir to the throne. When the crisis developed, even the German emperor thought it was not worth cutting his holiday short for.
