Sometimes Gms want that. they would rather not want people destroying their story by say turning the world upside down using some craft alchemy and real world knowledge to make black powder. now I am not saying they are good Gms but they are typically new, sometimes they are extremely daunted by the task of having to come up with things on the fly, a lot.

Some simple solutions, if anyone in the group is good at gming offer to give them advice. or try Gming a game for them let them be in a very open world and if they get excited they might try incorporating it into their games.

I also am going off some assumptions that everyone in the group is new excluding yourself. Maybe its something the gm does because they didn't learn what its like to be a player. I was once a gm like that though I was lucky as I had always planned an open world, but my first players had almost never played an rpg at all, except one and he understood why I made it a tad more linear.