you are conflating everything that isn't your preferred style with railroading, which is almost universally considered to be bad GMing. In other words, you are, unintentionally or not, calling everyone else a bad GM.
I am talking about my experience of play.
Suppose that person S is a GM. Some players play a game with S GMing them, and enjoy it. Others play the same game with S, and don't enjoy it. S asks "Why didn't you enjoy the game?" Those other players reply, "It was too much of a <insert negative description here>." The
least useful and meaningful thing that S could do would be to quibble with those other players over the description they've used, on grounds that S doesn't agree with them that the game fits that description. Obviously S doesn't think that S is a bad GM running a bad game! But, given that - as many in this thread have pointed out - tastes and preferences are diverse, S's confidence that S is a good GM using good techniques to run a good game is no guarantee that people will agree. And pointing to favoured online definitions of various adjectives used to describe RPGs won't change that.
So, in the spirit of the parable about S, I am not asking anyone to describe themselves as a bad GM. But I am making it pretty clear that there are some approaches to RPGing which, if they are used, will make me leave the game because for me it has various negative qualities that I have ready-to-hand adjectives to describe. And this is not conjecture - I've done it, on three occasions.
You talked about going to different countries, some of which were very different. Were you a space alien there? Did you require "levers" in order to act?
No, you weren't. You may not have known the customs and traditions, but you learned them.
But not by being told by an omniscient narrator, except on those occasions when I actually looked in my Lonely Planet.
And in a RPG, you learn things, in large part, by asking the GM for the information. This doesn't mean that they are dependent on the GM to give them "levers." All it means is that the player wasn't the one to make the setting.
This means that all the imagination is coming from the GM. Given that RPGs - at least as I enjoy them - are a form of shared imagination, this is a fail state.
So, serious question: how much can a GM make up before it becomes too railroady for you?
What unit of measurement are you asking me to use? I mean, I've told you how I enjoy play. I've posted multiple examples. I've linked to actual play threads. Are you really saying that you don't get what sort of play I enjoy, or understand how the different participants - players, GM - take part in it?
And a follow-up question: how does your preferred gaming style deal with mysteries, horror, and other elements that normally require the players to not know what's going on?
In a thread that you participated in a year or two ago I made a long series of posts, some in reply to yours, explaining how a mystery might be set up and adjudicated in AW. The first of those posts is here:
https://www.enworld.org/threads/thoughts-on-apocalypse-world.682898/page-12 Numerous further posts follow that one. They provide a very detailed answer to your question, with worked examples.
Burning Wheel is not identical in procedure, but the basic ideas are the same.