True, I wouldn't propose that it's a direct cause-effect relationship like the relationship between hitting a football with a kick and the ball accelerating.

Not to mention that discontent itself has causes

Everything is related to everything else, sure discontent has causes. What I would propose is that we can explain a lot of things when we take the view from the perspective of discontent so to speak. I would never deny the fact that things in the environment influences discontent, and that discontent eventually influences the environment. The world is too complicated to be properly understood in a reductionist paradigm. That doens't mean though, that a lot of things can be illuminated if we take discontent as a constant.

I like to see the world as consisting of different, I don't know what to call them, gravitational centers of phenomenons... Exemplified by discontent, I understand discontent more as a thing that "gravitationally" makes more likely certain kinds of phenomenons, than a cause of these phenomenons. I use the term gravitation only in the hope that it adds a figurative, qualitative understanding of what I mean, it is in no way a formal expression of my idea.

Of course, if you frame it right, you could say that discontent caused the industrial revolution as well, but that can apply to anything.

Allow me properly define what I mean. When I say discontent I mean dissatisfaction with the world as it is. Being consistent with my former conception of "gravitation", I would have to say that discontent more or less pulled us in the direction of something alike the industrial revolution (or rather, it pulled us towards this characteristic exploitation of technology and science allowing for the industrial revolution).

Discontent can also cause minimalism.

It seems you caught me on point where my theory falls down on itself. Discontent is not a sole cause. I will maintain that withholding discontent even if you are going in the direction of minimalism will cause you problems, though the problems will be much more of a personal nature, and much less visually startling. Discontent is a never-satisfied driving force. What is causing the world to externalize discontent materialistically as opposed to internally by reducing the our relationship with the material world, I don't know. It seems to me that there's at least two things at play here. There's a thing that points us in the direction of materialism, and then there's the fire of the whole machinery, discontent.

My conclusion would be that discontent is a necessary but insufficient condition for a thing such as mass consumerism.