I don't think the passport is an invention itself, so to speak.
Travel like that was never "reserved" for explorers, missionaries or high ranking dignitaries. If you had the money/resources, you could go anywhere.
Now there is a "caste" system of countries that have Visa on Arrival, Free Entry, or Visa required where you have to prove that you are financially capable, or even wanted in the country, or promise not to work or be illegally employed/compensated.
And then that alongside many countries in the developing world that still have undocumented people, no birth certificate, no identification, no tax ID, etc.
How does a country verify someones birth? Especially if someone wasn't born in a hospital? In the west, until 1950's, mostly this was done via church records. Also, are you granted citizenship by birth or only through parents? (Big deal, especially for Puerto Rican births - or countries that don't recognize foreign births in their land, e.g. United Arab Emirates / Saudi Arabia - even Japan or China, where sure you can be born there, but that means absolutely nothing.)
So, no, it isn't really a greater system for international worldwide travel - it is a system of control to ensure someones identity is who they are and that the country they are form atleast certified to some standard that their name, their picture, their birth date, their location of birth are somewhat tangibly real.
And this isn't even getting into information sharing. The above is just a standard, that now is "machine" readable and has an RFID so that collection is more easier for the state.
Context is amazing, isn't it?
Why 1800s? Why not Roman times? All you had to do is state you were a roman citizen, and you could travel - Unimpaired “ Civis Romanus sum”
https://en.m.wikipedia.org/wiki/Civis_Romanus_sum
Borders existed but travel was not impaired, how else do you think trade and commerce worked? Do you think supply chains are a new thing?
It very much sounds like you are conflating serfdom, as an impairment to free travel - it is a different exercise. Because you did have a king, and you were a farmer in that land and in many ways you had lesser rights than a slave.
The Roman Empire was a unique example among the thousands of years of history because along with their transportation network of roads they did actually have a couple of passport-like systems in place. Now a third of the people were literally slaves, so they definitely weren't going anywhere without permission, so maybe Rome is not a great starting point for what I presume to be the argument against passports. But the Romans and other Mediterranean civilizations did check your identity when you travelled. Romans had documents they called diplomas for people on official business and several civilizations used clay tablets called tesserae as a sort of ID card, but by far the most common method was simply having known people vouch for you.
Basically nowhere in the ancient world from the Middle East to the pre-colonial Americas could you just show up in a foreign village without people asking questions that you ought better have good answers for. There are a handful of exceptions, but this has never been the norm, and even with passports and visa restrictions it is definitely far easier today than it ever was in the past. I expect it will get easier and easier into the future. Perhaps quite soon in fact as the global population begins to decline and people become more and more valuable.
Consider how the days before passports also lacked air travel available to the masses. Even cars has only just started to become commonplace. I don't see how you could possibly have travel that is so cheap, quick, and accessible to such a large population without some way to control who is coming and leaving your country? Especially with how we're quickly making different parts of the planet inhospitable, and given how rapidly populations have risen compared to a century ago.
Passports are much older than that, but in pre-WWI Europe, most countries didn't require them for travel. (Russia and Turkey did.)
Passports certainly do have a dystopian element to them, especially if they are demanded too frequently / aggressively. But on their own, they aren't particularly evil; they just identify you much like your face does.
> Before WWI there were no passports and no need for them.
This combination of ignorance and confidence isn’t a good look.
So unless private collection of personal data is completely illegal, I’d rather have a centralised ID system instead