darjr
I crit!
I think you could. A big sandbox or dungeon. Make no story but set the scene and what the NPCs want and will do without interference.I would go so far as to say that it's impossible to make a large-scale adventure that doesn't have a significant element of railroading in it. Those are more properly termed sourcebooks. Or, I guess, dungeons.
I think it's harder to make, harder to run, and probably harder to sell.
I also have a "take", I think most players want a story. Or they want to play that story, which isn't the same as passively watching a TV show or reading a book. Definitely more "railroady" than an open sandbox or variant path dungeon.