Common accepted knowledge around here is that greed is good and that capitalism works because of it.

Fine, let's accept it.

But here's my pet theory and here why I think we see cracks forming up in this "greed is good" mantra (which, frankly, hurts common sense of anyone living in a judeo-christian culture, because, well, isn't greed a sin?): this only works in a world of expanding EROEI (Energy Return On Energy Investment).

This cheap energy is basically a giganormous pool of energy slaves. As long as there are slaves to capture, greed is good because it's good for everyone to capture and distribute as many slaves as possible.

When that pool dwindles, greed stops working as well as it did for the advancement of public good and it begins cannibalizing on it (the public good). It still gets accepted as a truism today, but it will soon go back to sin territory.