If you "bring down the current system", do you think what results is going to be less destructive to the environment? Or will 8 billion people all do whatever they have to in order to survive, regardless of the damage it causes?

You have to have a realistic replacement for the current system, and a realistic plan to get there. Without that, bringing down the current system won't lead to something better, but to something worse.

We have a model for what happens when you “bring down the system”. Do you think it would be better if we were all living in the equivalent of Somalia? It can be very difficult to engineer a stable revolution and all too often it ends up in chaos.

> We have solved nuclear fission power, created vaccines for COVID, and went to the moon. Surely we can go back to a world of greater sustainability than now.

I'm not sure about that at all. These three things you listed are just science/technical problems, while the latter is a governance problem. Governance is much harder than science and technology.

So you don't actually want to "tear it all down", yes? That would indeed be very stupid. Revolutionaries almost always make things worse, and often has wicked motives. Reformers can make things better.

Unfettered capitalism is certainly worth criticism. A just economic arrangement is one that rests on a sound philosophical anthropology. Of course, a good portion of those raging against "the system" are driven less by moral concerns and more by envy masquerading as moral concern.