POINT TWO The Enlightened Despot can never fall! Wait, why don't they exist anymore? Prussia in the FeR timeline was not in a good position at all. It had lost the Nine Years War, a large war involving many major powers from the Austrians, to the Russians, the British and French, and of course, the Prussians. Many more were included as well, but i'm not going to go into it here. You can read it on the lore post here: https://www.reddit.com/r/FdRmod/comments/khiwdb/the_prussian_republic_the_beacon_of_democracy/ggl9710/
The effects of the 9YW were rather harsh on Prussia, and the best way to argue this would be to quote it from the lore itself, so that it is as accurate as possible.
Prussia had lost the Nine Years’ War, but the peace was not exceptionally harsh, or at least so it seemed on the surface. The only territorial loss was a section of its 3rd Polish Partition, around Grodno and Byalistok, which went to Russia. Prussia also had to acquiesce to the vast rearrangement of the Holy Roman Empire following Austria and France’s whims, known as the “Mediatization”. Indirectly, Prussia was disadvantaged by this process, as most of its territories had already been strongly integrated with the Crown in Berlin and there were little to none small territories to be annexed into the kingdom (even if there had been, it is unlikely either Austria or France would have been generous with Prussia). After the events of the Nine Years’ War, the Habsburgs as Holy Roman Emperors took steps towards modernizing the institutions of the HRE. The Perpetual Diet that had been functioning in Regensburg from the late 17th century was disbanded both due to the city’s support for the Prussian cause in the war and because many considered it to have become “hopelessly powerless”. Instead, a Reichsrat with modernized legislature was put in place in Nurnberg, reinstating this city’s old tradition of hosting the Diets. Nurnberg’s neutrality in the war certainly helped its cause. The traditional three-layered house layout (Electors’ College, Princes’ College, Cities’ College) was kept, but their attributes and means of interaction were revamped. The Reichskammergericht (Imperial Chamber Court) was further strengthened and given full judiciary independence; the competing Aulic Council from Vienna was disbanded, thus elevating the R.k.gr. to supreme court status. Due to its small headquarters city of Wetzlar being annexed during the Mediatization, the R.k.gr. was moved to its city of origin, Frankfurt am Main, which was still a prosperous Free City. One of the primary topics of debate in the early sittings of the Reichsrat in the 1830s was the establishment of a customs union. That policy was finally implemented in 1840 with the establishment of the Zollverein. All these reforms gave the HRE a semblance of relevance and modernity, and helped to further the Habsburgs’ dominance of its affairs. On the shores of the Baltic, Prussia was increasingly dissatisfied with these developments; it actively sabotaged the Zollverein by not taking part in it. While this served to show that Prussia was still a relevant opponent to the Habsburgs, this boycott did more to hurt the Prussian economy than it did to affect Austria, either economically and politically. In terms of the reparations that Prussia owed Austria and especially France since the Nine Years’ War, the king chose to fulfil the payments mostly by increasing taxation across the board in the country, from the peasant to the artisan, but excluding the Junkers, who yet again lobbied to not have any measures taken against their old privileges.
TLDR: Prussia lost land, lost influence in the HRE, and was hit hard economically.
Oh, but that is not all.
Prussia tried to now deal with their Austrian rival via subversion, and supported general Gyorgy Klapka’s Hungarian rebel army as they launched another freedom fight in 1866. However, this failed, and with clear evidence of Prussian meddling, Austria had the perfect casus belli and launched into Silesia. However, the army was rather subpar, quoting from the lore.
However, the almost-constant budgetary deficit that Prussia had experienced since the disaster of the 9 Years’ War meant that the Prussian Army did not reform into an efficient, meritocratic war machine, in spite of Clausewitz’ attempts to reform in the 1820s. The Junkers kept many estate privileges, limiting the efficiency of the Landwehr mobilisation. Promotion to positions of command was still many times done on the basis of lineage rather than talent. The lack of funding throughout the 1840’s and 1850’s also prevented the Prussian War Ministry from funding and producing Dresye’s needle gun designs, which otherwise would have drastically improved the firepower of the Prussian soldier.
Due to Austria’s newfound influence in the HRE as well, Prussia now also had to deal with many HRE states who had chosen to side with their rival, and soon began to lose the rest of the war. For more detail, you can view the main post here: https://www.reddit.com/r/FdRmod/comments/khiwdb/the_prussian_republic_the_beacon_of_democracy/ggl99tr/
The result?
After the decisive defeat at the Battle of Breslau, Prussia sued for peace. The Treaty of Prague (1870) saw Prussia lose Silesia to the Austrians. Furthermore, its position within the HRE was weakened even more, as most states came to accept Austria’s dominance by this point, and Prussia was compelled to join the Zollverein, further subjecting its economy to Austrian hegemony. The Austro-Prussian War (1867-1868) ended in a decisive defeat for Prussia. Silesia was annexed by Austria and the country’s political and military leadership was thrown into disarray. Prussia would never really recover from this and 10 years later events from Berlin would shock the world.
So, the stage was set.
With such poor performance in recent wars, a crashing economy, a rapidly aging military, loss of influence, and their rival emerging as utterly dominant over them, the first person to blame, would be the king. After all, it was the king in charge of the country, and it was the king who had led the country into this state. At least, thats what most people would feel. How could an enlightened monarch be designated to rule by god, if he had caused such ruin to our country? It was ridiculous.
Not only that, it was already 1878 at this point, and while revolutionary ideals did not spread as fast as it did IOTL due to the lack of the Napoleonic Wars, they had slowly begun to creep into modern day society. Combine this with the lack of proper reform and liberties by Frederick the Great and a series of wars lost and economic troubles by the following kings, well, its safe to say people wanted better.
The people wanted more rights, more liberties, and most importantly, the end of what they saw as a useless and incompetent monarchy. To rule themselves, they figured, would be the best way to ensure that such failings never occur again.
After a series of bad harvest seasons that saw grain prices rise exponentially, it broke the last straw. A violent revolt broke out in Berlin, and thus began the Prussian Revolution.