I think the point the article was trying to make is that capitalist institutions will still exist, they just won't be the focus of everything the way they are now. For most of human history, the focus was on feeding everybody. Right up until the start of the industrial revolution just about everybody worked the land to provide food. Now only 3% of the workforce are engaged in agriculture. Our need for food hasn't gone away, but it's a solved problem. We work on other problems instead.

Now, imagine a world where running the factories, the distribution and all the other jobs which currently needed to supply all the consumer desires only takes up 3% of the workforce. If we add in the 3% that we still need to grow food, what will the other 94% do with our free time? That is thinking about post-capitalism. Capitalism won't have gone away, it's just advanced to same point as agriculture, where 90% of us can ignore it.