Moving away from all the miserable stuff (convincing yourself it can't be done is the death of action)
I stress that nobody here claimed that triumph is impossible. Merely that implementation of your suggested goals and methods,
in the short term, seems exceedingly implausible. I'm happy to move on from that whole line of discussion, but remain eager to receive even a single example of a Western country that has forcibly assimilated or expelled the bulk (let's conservatively define that as >50%) of its non-Western immigrants. Once you can point me to such an example, we will have reached the start of the next great turning, and your suggestions will have become viable policy.
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I have noted there are other figures who are almost "Augustus" like throughout the world. Although I think I'd disagree with some by saying the Asian Augustus was not Qin Shi Huang, but Tokugawa Ieyasu; a man who in all honesty was more formidable than Augustus himself.
In Britain's case meanwhile, I'd give that honour to King Alfred the Great.
What
@Cherico noted re: the comparison of Augustus and Qin Shi Huangdi (indeed, Gaozu is the proper analogue). Besides this, however, I'm not sure that conflating a "national" hero-king to a "civilisational" hero-king (or rather: emperor) is the right track.
Alfred, very crudely put, is like the English "national" iteration of the same archetype that produced Charlemagne in a somewhat more universal "European" fashion. He is the uniter and founder of the realm in its quintessential form.
I do see a strong basis for comparison between England/Britain and Japan, in that they are both island-realms off the coast of a continent that houses a developed civilisation; that both of these island-kingdoms have been influenced (at times very strongly) by continental culture, but typically put their own spin on things; and that their histories (up to a certain point in time) follow a remarkably similar track.
However... just as Henry Tudor was not the Western Augustus, I strongly feel that Tokugawa Ieyasu was not the East Asian Augustus.
That explicit comparison already indicates my line of thinking, which (to some extent) I've detailed in
this thread, where I tried to set up for a Britain whose history follows Japan more closely-- including a "Tokugawa period", with an equivalent of
sakoku.
My general interpretation is that while it is accurate to say that Japan didn't really have a
true analogue for the Anglo-Saxons, we can still argue that there is a basis for historical comparison, going back very far. Japan in the Jomon period is more or less "analogous" to pre-Roman Britain, in my interpretation, and I cast the arrival of the (external!) Roman influence as being akin to the emergence of the Yayoi period in Japan. It is now generally understood, after all, that the Yayoi people were formed around a nexus of migrating groups from the Korean peninsula. They brought external culture unto the island-realm, but by and large, they we not numerous enough to demographically supplant the native population. (Much as was true for Celtic Britain during the Roman period.)
I am inclined to carry on that comparison, and liken the influx of ethnic Han migrants during the Kofun period as being at last somewhat similar to the arrival of the Anglo-Saxons. Sure: purely periodisation-wise, the Kofun period happens in the era that is
temporally equivalent to the age of Sub-Roman Britain, and the Kofun-era migrants didn't shape Japan quite to the extent that the Anglo-Saxons altered the fate of Britain... but there are at least some similarities. After all, the consensus of historians tends more and more to recognise that the Kofun influence (both as far as culture and genetics are concerned) has been wrongly downplayed in the past. They played a more major role than was previously thought.
Now we come to Alfred the Great, because the subsequent consolidation of the central monarchy in Japan during the Asuka period can be seen as similar to Alfred's consolidation of royal power in England, ending the divisions of the Heptarchy. Indeed, even the introduction of Buddhism in this era can be seen as very much like the introduction of Christianity into Anglo-Saxon England. This suggests to me that the most plausible "equivalent" to Alfred in Japanese history is probably
Tenji, although this equivalence is not exact. Alfred basically did more by himself, whereas in Japan, equivalent steps were taken by three separate rulers who reigned in quick succession. Tenji being the most prominent of them, who basically brought about the "crowning achievement".
...Now, hereafter, Japanese history remains quite similar to English/British history in various ways. There is even the characteristic conflict with other populations/realms that represent an older native demographic cohort-- and who are ultimately overcome in a series of conflicts across the centuries.
There is, however, a major difference, presumably caused (at least to the greatest extent) by the fact that Japan is significantly further away from the continent next door. Britain historically saw more invasions and invasion attempts, and conversely, was engaged in more direct involvements on the continent.
Of course, before any serious centralised state formation, the islands of Britain and Japan both saw similar patterns of migration from the continent, which suggests that the greater distance isn't
that overwhelming a factor in all of this. It just seems that once state formation got underway, the greater distance combined with "actually having to make an effort" discouraged most would-be invaders of Japan. By contrast, Britain continued to see invasion attempts.
But not all that many. And practically all of them failed. The Channel is a pretty impressive moat. Even with the reduced distance, compared to what Japan has, the same scenario of "
would-be invasion fleet gets totally wrecked by unexpected storm, ha ha fuck you" actually occurred in both cases.
Conversely, the differences
are clearly there. I see no Japanese equivalent of William the Conqueror; I see no Japanese involvement on the continent such as that of the English in the Hundred Years' War. This suggests to me that Japan was, from the start, more "isolated" than Britain could ever be. Regardless of that, though, Japanese history continue on otherwise quite similar paths.
I view the Wars of the Roses as a British equivalent of the Sengoku Period. Sure, the Sengoku Period in Japan lasted a century and a half, and the Wars of the Roses lasted only three decades. But then again, the Hundred Years' War was also a cause of considerable disturbance, and it preceded (and to a considerable degree, led to) the Wars of the Roses. (And per my previous analysis, I'm pretty sure that if Britain has been less involved in continental affairs, it would have fought its own internal wars
instead of the Hundred Years' War, anyway. Much as Japan did.)
This then brings us to the point where I started this lengthy comparison. What is Bosworth Field, if not Britain's Sekigahara? The battle where an entire historical period is brought to an end; whereafter a new era commences. It even has the same backdrop of notable defections, and the same aftermath of "mopping up" as straggling pockets of dissent are crushed.
Britain's history being less isolated, the natural direction of the new period was one that led to a great opening. Japan, instead, had its great period of closing-off. This is where the underlying divergence
really manifests. Which is why from that point on, further comparisons become far more tenuous.