Um, just read the linked article. "The population of smart machines would explode even faster than the economy. So even though total wealth would increase very rapidly, wealth per machine would fall rapidly." Robin Hanson is not a self-declared "Singularitarian", but I, his co-blogger, certainly am, and we had a discussion about the effects of future resource constraints on intelligence here:

http://www.overcomingbias.com/2008/05/biting-evolutio.html