The Balkan wars you mention are exactly the reason why Austria prepared and wanted the war against Serbia: they estimated it would be a fast win, as Serbia's resources must have been drained in these wars.
They somewhat miscalculated how the other countries would react and the World War ensued:
No, Germany's actions actually make pretty good sense.
Remember that the Archduke was shot in June. A month before Austria-Hungary declared war. In this hesitation, France tried to heavily influence the United Kingdom to participate.
The Entente alliance between France and Russia was what the Germans had feared in a war with either power. That if they attacked Russia, France would join, and vice versa. This led to the creation of the Schlieffen Plan. The idea was simple: First subdue France by a huge force and then take Russia.
The thinking was that Russia would take too long to mobilise its troops to be ready, and in the meantime, the Germans could (in 4 weeks according to the plans) force France to surrender. Then the armies could be moved across the continent and be ready for Russia.
Beyond the fact that generals have made changed to the plans since its initial creation in 1905 (such as lessening the imbalance in troop deployment between East and West), the plan also made certain inaccurate implication; particularly regarding Russian mobilisation. Or rather, they did not anticipate the success of the French ambassador to Moscow in convincing the Russians to attack before they were ready (which cost them an entire army), but still forced the Germans to redraw two entire corps from the Western front to the Eastern front.
Germany tried to telegram France and Russia whether they would participate. Russia's mobilisation was a confirmation of the fact, while France simply replied 'France will do what is in her best interests'. Germany took that as France will come to Russia's aid. Which also makes sense, because France was really hoping to undo the damage of 1870 and win back Alsace-Lorraine.
The United Kingdom was at first incredibly reluctant to get involved in a war on the continent. But France insisted that if Germany violates Belgian neutrality (which they did on 3 August), it would be a direct violation of the 1830 London Conference regarding Belgian neutrality.
Germany thought the British would not be foolish enough to go to war over 'a piece of paper' as the German Foreign Minister told the British ambassador when he delivered the declaration of war.
And all because Germany had promised Austria-Hungary they would come to their aid in the event of war.
It is not without reasoning that Otto von Bismarck himself was opposed to the annexation of Elsaß-Lothringen, because it would create an unneeded rivalry between Germany and France. Had France not had that interest, France would probably have been far less inclined to participate.
Not a month, it was only 3 days between: 28 July, 1 August. And the war of Austria was against Serbia. But Germany was fully ready to both declare the war on Russia and attack France, in 4 and 5 days (first Luxembourg). No country is so prepared and ready by accident. Germans were obviously waiting for that too.
Archduke Franz Ferdinand was assassinated on 28 June. Austria-Hungary declared war on Serbia on 28 July. That's a month.
And it's the period between 28 June and 28 July that real negotiations and build up happened.
And yes, Germany was ready. After the second Balkans War, Austria was interested in a war with Serbia. But while Germany supported Austria, Germany insisted that it would not be ready for such a war (anticipating a Russian response) until mid-1914, and responded to Austria (in 1911) to that effect.
> Germany insisted that it would not be ready for such a war (anticipating a Russian response) until mid-1914 and responded to Austria (in 1911) to that effect.
And mid-1914 it was.
> it's the period between 28 June and 28 July that real negotiations and build up happened
And obviously all that buildup on German side was not only that month, but planned and executed for years, per your 1911 reference.
The month was used by the French to convince the British to participate. My point is; had Austria-Hungary acted faster, Britain might have entered the war too late to help the French.
They somewhat miscalculated how the other countries would react and the World War ensued:
https://en.wikipedia.org/wiki/Timeline_of_World_War_I
"July 28: Austria-Hungary declares war on Serbia. Russia mobilizes.[4]
August 1: Germany declares war on Russia.[5]
August 2: Germany invades Luxembourg.
August 3: Germany declares war on France.
August 4: Britain declares war on Germany."
That will teach these Luxembourgians(?) And the French(?) too.