With a few bright exceptions like Robin Hanson and Paul Wallich, the IEEE Spectrum issue follows the usual pattern: People who have no engagement with the serious Singularity analysts, making up stuff at random and saying "This is what the Singularitarians must believe."
I'm not sure why, but I've never heard singularitarians consider that computation and intelligence is bounded by more hard constraints, like physics, than will let exponential growth continue indefinitely.
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:
Of course, but we're not anywhere near the physical limits. An analogy is that it's clear that molecular nanotechnology is feasible, and consistent with known physical law, even though we don't know how to engineer MNT systems.
The "extrapolation of exponential growth = 'Singularity'" idea is a really crappy argument, and you shouldn't give much weight to it. For me it comes to two postulates: 1. AI is feasible. 2. When AI arrives on the scene, large changes are in store.
But I'll play my bets and say that NP-Hard will stay hard, the speed of light won't be broken, and at a certain point you need to switch to reversible computation because of landauer entropy, which will set space constraints of it's own.
Check out "Tom Lord"'s comment towards the bottom of the page-- interesting take, but definitely a reach.
Nevertheless, it's something to consider, that maybe the growing popularity of the Singularity notion is the next sociopolitical movement on the scale of the 60's counterculture era... allowing people to escape from where they currently are by considering and believing in the vague notion of a distant future where things are different, but they're not sure how... and that is why they spend time thinking about and working towards their vague, alternate perception of what reality is.
I'm not saying this is true, that technological trends do not point in the sign of the concept of Singularity- in some way, shape or form- actually happening. This viewpoint merely resonates with me because of the historical reality of what we've seen with previous movements (and this extends beyond just 60s United States).
I think that's the most amusing take on the singularity I've read so far.
But seriously, the singularity as such is just a name for the point passt which it is not possible to make predictions right now. As such it's an ever retreating goal, like trying to visit the horizon.
The term now has at least three major separate meanings, by the way. See http://www.singinst.org/blog/2007/09/30/three-major-singular... for preliminary disambiguation.