Economic competition and imperialism as causes of WW1

Comment on the following saying you agree but don’t spend too much time on the alliances and assassination.

The assassination of Archduke Francis Ferdinand by a Serbian nationalist was the immediate spark which ignited the First World War by triggering the intricate system of alliance and alignments developed during the nineteenth and early twentieth centuries. However, the assassination and diplomacy, though very important, were not the underlying causes of the war. Nationalism, the struggle for colonial empires and economic competition also helped set the stage for the bloodiest war the world had ever known up to that time.”

Prove that the battle line for WWI was drawn before the assassination and all sides had been preparing for the inevitable war. A little on how the alliance system although important, not the main cause as it had kept Europe in peace for decades during Bismarck’s period. Darwinian nationalism, economic competition between Germany and Britain, Imperialism … are causes of; the war is your position. Also, spread the blame on everyone not just Germany for starting the war. I am having this rewritten because the first writer made it look like a history book by just stating what happened and making it so dry. Please take a judgemental tone to make it more lively and argumentative. Thank you!!