This has nothing do with cynical George Lucas-style profit maximization. It's a simple fact of technological progress. Since consoles are typically designed for a 5-10 year lifespan, the technology involved inevitably shrinks over that period and enables a smaller and more efficient package.
As a comparison, I don't think Sony originally sold us giant boomboxes just so they could "get us again" when they came out with the Walkman.
Not sure I agree with the article. Would a company the size of Sony play a strategy like this? I suspect the real reason is that the design of the casing just hasn't been finalised yet. Nintendo did something similar with the Wii as I remember, but the other way round, announcing the the hardware look/feel first and the Wii remote and launch games at a later date.
Sony's initial releases are larger than later slim versions for the same reason that computers used to take up entire rooms and now fit comfortably in your pocket. Given that it's not releasing till around the end of this year the design probably isn't finalised and they don't want to show it till it is.
The original PS3 was a huge box, but it wasn't full of air. It was filled with cutting edge tech hitting thermal limits. It's hardly surprising that over a 7 year lifespan the system can be miniaturized.
As a comparison, I don't think Sony originally sold us giant boomboxes just so they could "get us again" when they came out with the Walkman.