I get what you are saying. I just don't think you get what I am saying.
What I am saying is that from the player's perspective it is meaningful that he doesn't know that behind the scenes they have options A through D and that it is meaningful that the GM hides the rails by not explicitly outlining what the choices are.
But this change of experience is not necessarily a real change in the situation, and it doesn't invalidate what I am asserting which is that the choices the players have are always the ones provided by the secret keeper. In reality it's like playing a Choose your Own Adventure book where someone else is holding the book, reading it to you, and letting you guess what your options are or ask questions that may provide you hints as to what your options are. And in that situation you can't know if all choices lead to page 38.
No, I get what you are saying, this is how RPG scenarios have been made since AD&D, though perhaps not with such stark (and detailed) option listings at each stage of the adventure. I've seen various adventures say, "if the players do X..." with some ideas for how to handle, but I don't think it's inherently necessary to worry about every direction a scenario might go, and even think it might be self-defeating. (Of course, if the dungeon passage forks right and left, they have the option to go right, left, back where they came, or to make camp, but that's just the options they have in the "real world." I'm talking about larger decisions than this, say like "infiltrate the castle.")
A better way to do things is to detail the situation, the hooks, the background, the NPCs, any events, and then play out the hook scene for the characters, and then see where the players go with it. This way you're not too worried about whether the adventure goes a particular way, or trying to force a particular path. Now it is important to build really strong hooks and clues and events that lead characters to follow up on things, but if they choose to go about it in a different way, that's okay too. I actually dispute the need for the referee to come up with all the options, though I do believe it's good to carve a most likely path and have signposts leading in that direction. And be prepared to deal with anything arises in the sphere of the adventure. Maybe that's not too different from what you are proposing, but I think the subtle difference is important.
I actually have no issue with "railroad" adventures (I've refereed and played in many), but the "railroad" is generally the hook, or an important scene that offers a strong incentive to go in a particular direction. But after that players can do what they may. An example is one where all the PCs start in a lifeboat from a wrecked ship, and in the storm, they see an island and lighthouse. Pretty strong incentive to get to the island and participate in the adventure, but once they get to the island, they can do anything they want.