They said this same thing last time. It did not happen.
The big difference between previous gens and this generation is there, aside from basic unique components, the major components within the consoles are not extremely complicated custom fabbed parts. It's generic x86 architecture. The overall package is unique to the consoles, but the R&D, fabs, production, it's all under control.
In other words, no crazy custom PowerPC architecture, no new media launching/getting the big chance to make a market penetration (DVD, Blu-ray). Hell, even most of the components haven't had major supply disruptions for awhile. DRAM should be good, though not at the cheapest point historically; HDDs are fine; fab tech processes at the node(s) they are using should be very mature; and again, customized but otherwise off-the-shelf technology will be a major player.
Do they have straight retail GPU architecture? Not entirely, but I'm sure they didn't actually make significant architectural changes to the GPU tech in each of the new consoles.
Granted - we are still talking a full computer, of sorts, with moving parts, moving probably between 250,000-750,000 units. There WILL be limited availability - but Sony is taking a careful measured launch (haven't looked into Microsoft), delaying a major customer (Japan) until well into the new year, with Europe a few weeks after North America. I think they'll have the ability to trickle in stock while stockpiling new production for launches in other regions.