The culture of a given place and time is filled with a variety of complex cogs and elements. Still, the origins of a “culture” arises somewhere; the memetics and development of fads and fashions of the time all have a beginning. So, who makes the culture?
First you can look at the artists. Without Kanye West, or Game of Thrones, or Harry Potter, the world would be a very different place. These artists and their art place a foundation to how culture is prescribed. Different echelons of culture take inspiration from different types of art as well; some communities may favor cultural expression with something like Game of Thrones, whereas others might take it in the direction of Sailor Moon or Black Dynamite. The important thing is that these pieces of art influence the direction of the subgroup in one way or another.
Of course, though art does define a good chunk of the culture, it does not define all of it. Current events, political or otherwise, also shape the society. Drawn out news fads can often leave a deeper, more subtler impression on the state as a whole. Turbulent political times frame the outlook of a society, which is then manifested within the culture itself.
So, in summary of these two points: we can say that artists “make” the long-form general culture, which is then, at fixed points, is affected by the stance of the current climate of events. This climate is the second largest factor towards developing the culture. I would then say, at a micro-level, group dynamics play the final solidifying piece in developing the culture. A group is given the art and the climate, and must develop their own unique narrative based on these concepts. And so, these three distinct layers form the final culture cake.