This could be like the opening of World War One.
I think you are right. Serbian nationalist terrorists killed an Austrian leader. (Bosnia was part of the Austro-Hungarian Empire, and Serbia claimed it). Austria demanded that Serbia make concessions, and Serbia refused. Austria and Serbia started shooting, then the system of alliances committed all of Europe to the fight. There are no alliances involved here, but it is a regional dispute that could get totally out of hand.
But, given modern communications and transporatation, much faster. With Nukes! However the presence of the nukes is more likely a stablizing influence, tending to make other nations think long and hard before becoming involved...all but most of the Islamist countries, for whom thinking, let alone long and hard, appears to be something of problem.
Yeah, if the jihadis fought like Germans.
Too bad they fight like Italians.