How important were Great Power rivalries as a cause of the First World War?

The origins of the Great War have instigated debate amongst historians for almost a decade; unlike the subsequent Second World War, there is no clear-cut culprit for the unexpected descent into world war that shocked the world in July 1914. Whilst the assassination of Archduke Franz Ferdinand in Sarajevo on the 28th June 1914 was undoubtedly the direct cause of war, it was simply the catalyst for the heightened rivalry between the Great Powers that came to boiling point at the time of the death. Other factors, such as tension in the Balkans and domestic socio-economic issues were undoubtedly important contributions to the First World War; however the long-standing rivalries created by Germany during the late 1800s between the Great Powers and the consequent tangle of alliances, were the most salient causes of First World War. The assassination of Archduke Franz Ferdinand on the 28th June 1914, whilst pivotal in the descent into war that ensued, is ultimately unimportant as any minor incident at this time would have been enough persuasion for the countries to go to war. Even with the Archduke’s relative unpopularity, and the unexpected compliance of Serbia to the harsh demands by Austria-Hungary, war was declared. The assassination was simply a ‘means to an end’: the countries just needed an excuse to alleviate their heightened rivalry and to dispel the tension with what they believed would be a short and effective war: ‘the assassination has often been described as the spark that would set light to a continent that was riddled with international tensions.’ Whilst the Second Balkan War of 1913 is paramount in explaining Austria-Hungary’s reaction to the Serbian supported assassination of the heir to the Austrian-Hungarian throne, it was colonial rivalry which created tension in the Balkans and the direct threat to the Austria-Hungarian Empire that made the war so prominent.
The long-standing military and colonial rivalry between the Great Powers after Bismarck in the 1800s was undoubtedly the most important long-term factor which contributed to the First World War. Military rivalry was the most salient as it played on the insecurity of the countries and led to a vicious circle of action and reaction which made the idea of war almost accepted: ‘these expectations laid down the broad lines of strategic planning, so that the general staffs were taking decisions that often committed them to irreversible military actions if war threatened’. Suspicion surrounding this was heightened by ‘the secrecy of diplomatic agreements as well as of military plans’ which ‘encouraged the powers to spend money and energy on developing their secret services.’ Europe became a ‘divided camp’; each group of alliances attempting to build up a ‘clientele’ of smaller countries in order to intimidate the other. ‘The existence of the alliance system above all conditioned expectations about the form a war would take if it broke out, and about who were likely to be friends and who enemies.’ The desire to obtain their own military security saw the Powers embroiling increasing numbers of smaller, ‘satellite’ countries in an almost inescapable ‘war pact’, making a descent into world war inescapable.
Thucydides, in his ‘History of the Peloponnesian War’, points to the insecurity of Sparta in the face of growing Athenian power as the main factor in making war inevitable, and this idea seems particularly apt in this situation. The security dilemma: the struggle for power in which every attempts to make the other feel less secure, in order to feel more secure themselves meant that any attempt by Germany to build up her navy was viewed as an intentional threat to British naval supremacy and, an indirect threat to the empire. What arguably could be Germany’s attempt at simply building her military strength in a bid to be taken more seriously as a world power rather than direct