The Backstory (Actually important)
From the current day to an unspecified number of decades in the future, a brutally efficient, totalitarian dystopia-state rises and runs basically all of humanity under its empire. It's not a conventional dystopia, nor is it actually that bad to its people. I drew inspiration from china and their social credit system, and many other of their surveillance/control systems.
It is run by a small council of leaders called the overseers, which are sort of appointed by some selection method, designed to find the best candidates possible out of the government organization, the 'state'. Not a dictatorship, but not a democracy either, the people shouldn't even know they exist. Beside them and their government, the 'state', a black box which runs society, are the massive corporate entities that support the overseers and provide the people with jobs.
They are the science and research firms that created the phase-gates, keidran, exoskeletons and accompanying military/terraforming equipment, and built the starships and dyson swarm. There is a digital, government controlled cash system, which is linked to a social credit system, which is linked to a worldwide surveillance and biometric tracking network.
There is no concept of privacy or opinion, and you are always watched. Maybe not maliciously, but the police can preemptively know when someone might commit a crime, and prevent it, for example. It is slow and insidious, taking control of the top of foreign governments with its corporate partners, and then slowly implement its systems without the people ever batting an eye, until they realize that they don't have any freedom, they self-censor as there are consequences for free speech, and they don't know who it is they are run by.
But the point is that they are brutally efficient, the people suffer in the sort term, but the long term is the bettering of society. With such efficiency, theres no need for the support of the free market to make interstellar travel possible, or for crime and war to impede progress. The 'free market' is really just run by the state, and so scientific progress is for them to pursue, regardless of needing incentive for the public.
They are cruel, but they have a point and a moral, and most importantly, you can't really hate them, they aren't a cardboard cutout villain, and they see themselves as righteous.
The Question
How long would it reasonably take for such an empire to gain full control of humanity, fast enough that the plot isn't too far into the future, but not so quickly that people catch on and rebellion and genocide ensues.
It's basically coercion, slow, imperceptible moves towards gaining control of all world governments enough to install themselves as a de-facto government. Of course you could argue that this is an opinion based question, but I'm not asking you to build my society for me.
But the question this post centers on is this:
When in history has a change this drastic ever happened? Where can I draw comparisons in history to this?
This is closer to a fact than an opinion. History is finitely large, and I cut out a very specific criteria for what the question refers to. I want to know when something like this happened, so I can gauge what the future should look like.
I know of two obvious transitions that I can compare to. The Informational Revolution, and the Chinese Communist Party. The information revolution is ongoing, right now.
Sixty years ago, you could tell someone they'd have a supercomputer more powerful than every IBM machine of the time put together and they'd say you're full of hot air. What will the world look like sixty years from today? Will things keep on picking up steam?
And another example is the CCP. A generation ago, under Mao, China was a third world country, but today, basically everything can and is manufactured there. They are approaching the bleeding edge and facing off titans that have never been challenged in recent history, like the United States.
Where else in history has something like this happened? If at all?
After Note (Skip if desired)
Before you berate me on how this system could never work properly, I know that already. The thing is that you're listening to the plot of a book a fourteen-year-old author dreamed up, me, and I am trying to fix the problems it had and organize the mess I left myself, but before I do that, I need to know how far in the future, and thus what kind of tech, they would have access to, to plan out this society.
I kind of did it backwards, setting the aesthetic and feel of the world and then setting up a society based on how I want it to feel, instead of the other way around.
I originally had it as a vague "cashless-society social-credit-system dark-cloudy-concrete-skylines and cold-heartless-megacorporations" society, paraphrasing myself from a year ago.
I remember listening to this, this, and this, and being inspired for the tone of this world. Even though we never see it (this empire proper) through the series of books I planned.
If you noticed they aren't that old, then you can guess that I only abandoned my ambitions for a few months, and am coming back to add the science and logic it didn't have.