Can Capitalism continue?

To go back to the OP - why can't Capitalism survive with less than 3% GDP growth?

If think Capitalism can and can not continue. What I mean by the terms that it might can is that environmental friendly industries such as renewable and sustainable technologies and power sources that can be profitable. Although the profit for dirty industry, food, cars and other certain traditional industries can't just grow and grow. It's like you said. We can't gain more profit and it's on a decline. But what also might keep the profits grow among big businesses around the planet is the replacement from older devices and products to newer, cleaner and better ones. Thus the population grows, I don't know if that compensates it to a present state anyway..
But I hope to see a big profit for environmental friendly companies in the future. And engagement from both governments of Earth and its population in the ways of environmental friendly terms.

Companies that thrived making buggy whips were replaced by manufacturers of carburators - out with the old and in with the new. Capitalism allows for this evolution.

Agreed. I don't see what Gliese is getting at really, but it doesn't sound like capitalism to me.

Marx's explanation as I heard David Harvey explain, which I vaguely understand goes something like this. In das Kapital volume ii Marx does a gedanken experiment in a society with just two classes workers and capitalist. He argues that demand comes from capitalist paying workers who then spend their money on goods and demand comes from capitalist buying means of production so total demand comes from means of production and the wage bill. The total supply that a capitalist creates in surplus is profit. Marx argues the demand for the surplus is generated by the capitalist. That is the capitalist create the surplus and create the demand for the surplus. In order for this to work it has be an expansive system by which you pay off yesterday's debts with today's expansion, a credit system. So the accumulation of capital is also the accumulation of debt.

Whether you believe this or not I still find it hard to believe that a steady state economic system would resort to speculative economics in such a large way.

I think the life cycle of capitalism is like the fusion cycle of a star. At first it has access to lots of available resources to spur growth like a young star has lots of easy fuel. Then it uses up this easy fuel and starts burning more exotic fuel more fictional speculative forms of capital like synthetic credit default swaps then it runs out of fuel and dies.