In the trad style, the GM is often tempted to prepare a plot before a session – usually not with the intention of limiting player agency but rather with the intention of providing the most cinematic and satisfying session.
OSR and storygames, as games and styles of play, were a reaction to the trad style of play that dominated the 90s and still dominates today with D&D 5e.
Ask anyone who’s used a box as a table or a cat-entertainment-device. Some games are built for those styles of play, sure, but you don’t have to use things for what they’re built. The way I see it: OSR and storygames are not types of games. Trophy Gold is a game designed so that you can play old school (or new school) adventures in a storygame style.