The issue in WWI was inherently conflicting interests and Great Power competition. The “entangling alliances” merely formalized those factors.
The only Power for which I’m aware that the existence of an alliance played a possibly definitive factor in its entering the War was UK and its guarantee of Belgium.
Yet even this claim falls apart on examination. Would UK really have been willing to stand by and watch as Germany took over Belgium and France, the likely result of a war with UK neutral? When this violated UK standard foreign policy going back many centuries of opposing any power that seemed likely to gain unchallenged hegemony on the Continent?
IMO, the definitive factor in the outbreak of general war was Germany’s belief (probably accurate) that their relative position vs. France and Russia was at its peak, and would only decline in future years as Russia’s political and economic reforms bore fruit. If Germany was to dominate Europe and the world, it needed to strike NOW.
This was a classic example of a pre-emptive war, just as Japan’s attack on the US was, and for very much the same reason. As such, they were example of offensive tactics used in what was perceived as a defensive strategy.
It should be noted that several countries, such as Italy, ignored their “entangling alliances” and acted in what they saw as their own interests.
Germany had such a treaty with the Austrians if memory serves.
The Dual Alliance?