We are? I find that a rather bold assertion. The main problem of the von Neumann machine is gathering and transforming enough materials on its own. If we need e

We are? I find that a rather bold assertion. The main problem of the von Neumann machine is gathering and transforming enough materials on its own. If we need enormous amounts of ore and factories to do that, so does the machine. It would need to be mindboggingly huge, also because it needs enough fuel to reach new sources. A tiny machine won't work, because it can't refine it's own materials. Really, the practical problems are being hugely underestimated.