Monarchy has steadily shrunk as democracy has steadily expanded. Following the recent war in Europe, which witnessed the downfall of all its remaining autocracies, monarchy has been left with scarcely a foothold on the continent. This has been the tide of political progress throughout the world; it is beyond man's capacity to resist it, being precisely what the ancients meant by the "will of heaven." "Those who follow the way of heaven prosper, while those who defy it perish."
The Enlightenment in China didn't ignite independently of politics of the rest of the world - Sun attended the 'Iolani School in Hawaii and was especially inspired by Western principles through American political history, in particular by Lincoln. (Sun is considered the father of modern China both in Taiwan and on the mainland, hence the institutions named after him in both places; I wonder if this strong American influence on his philosophy is taught in schools in Beijing?) But it's exactly his ancestry to both China's capitalists and (at least nominal) communists that is key. Both Karl Marx and Adam Smith were arguing for liberties and an economic order based on reason and material improvement, rather than on authority invested in monarchs by a deity. Sun wasn't afraid to point out problems he perceived with either's theses or the constitutions of contemporary democracies, and as a result he still isn't easy to classify in any Enlightenment ideology dating after the free-market/central planning split. Go back up and read that quote again - this was a revolutionary speaking, but (ignoring the spiritual rhetorical fluorish) these could easily have been the words of Jefferson or Lenin. It has echoes of Marx's inevitable current of history, and every American President's evangelism about the expansion of democracy.
But Sun was primarily concerned with the legitimate basis of governance and liberty - which Jefferson and Lenin largely shared - not with economics. In contrast, today's religious terrorists have more in common with yesterday's deity-justified hereditary autocracies. Even without debating the moral definition of legitimacy, we can look at the practical impact. Countries with strong, predictable, transparent institutions, along with freedom of speech and the press and assembly and open elections, are the ones with the most sustainable growth. Certainly at the two extremes of economic policy, having either zero safety net or absolute redistributivism would hamper development, but the imposed tax burden or lack of social supports turn out to be secondary influences on the fates of nations, after resilient institutions and liberties. When these conditions obtain, it is assured that the political system in question will have mechanisms to correct itself by allowing innovations (which sometimes shine through despite a bad system's best efforts.) It seems that Sun had deduced this early on, since he was willing to align with the communists even though he was not one. Little did he know in 1911 how seriously and literally communist revolutionaries in Russia and later in his own country would take the points of Marx's program for a dictatorship of the proletariat. And how curiously disinterested they would be in its eventual dissolution, as Marx also wrote.
It's also worth observing that although China's communist government appeared later than the Soviet Union's, China's anti-monarchist revolution occurred 6 years earlier. This might lead us to ask why China had a 38 year interregnum between its revolution and the establishment of its lasting government, when Russia's was less than 1 year. More generally it's also worth asking why the U.S. was so fortunate in terms of instability. The U.S. had a 6-year interregnum (the Articles of Confederation) from the official end of hostilities with Britain to our Constitution, but very little fighting, even including my own pugnacious home state of Pennsylvania. Compare these light casualties to the post-revolutionary histories of Mexico and even France. Why was the transition in America so relatively tranquil? But these are separate questions.
In the end, Sun was at heart a patriot who wanted to see a stronger China, and patriotism is a relatively recent phenomenon. When your master and de facto owner is Louis XIV or the Tokugawas, why bother being proud of being part of a French or Japanese nation? Why did it matter if any subject liked or approved of their government? The idea probably would have seemed a little precious and naive to le roi or the shoguns, and puzzling and pointless to peasants. As such, Sun initially approached the Qing court with suggestions for a stronger China. These were either rejected or ignored. In the Qing Dynasty, if you weren't Manchu, your chances of having any influence were slim, although you still had some chance of access to the inner circle of you were willing to jump through the hoops: learn the classics and pass the civil service examinations, all relatively costly signaling that you would devote all your attention and time to the pointless exercises set by the Qing, rather than doing something useful and merit-based. Sun wasn't willing to do this, and many sources connect his turning from a would-be reformer to a revolutionary to these experiences in the mid-1890s. (Modern corporations and governments take note! Do you want talent, or do you want people willing to submit to mindless ritual?) But the Qing were not long for the world, and the resources they forced their best-and-brightest to waste on hoop-jumping was doubltess one factor in their demise.
Finally: the Western world would benefit from a new, well-researched account of the colonization of the New World, as well as of the classical era from the Battle of Marathon through the fall of the Western Roman Empire, by East Asian authors. Doubtless there are artificial distinctions we make and myths that have been promulgated for centuries that Westerners no longer notice or question, and that Asian writers would quickly identify and explode.