I'm actually the first to say that A: it's all energy and atoms in the end and B: the universe is awash with both and it's mostly our own stubborness that prevents us from claiming both since we don't "like" nuclear. However, even a Kardeshev Type III civilization will have to contend with the fact that its resources are finite, and as rapidly as its ability to exploit them grows, its desires are likely to grow even faster.
It's not capitalism that causes that, either... a great deal of our desires expanding faster than our resources predates the entire concept, and the problem will likely outlast it as well.
