The Sandy Bridge series of central processing units had a good run, but their time is drawing to a close, so there already are details on when the phase-out will begin.
On the IT market, when a product or product line phases out, it gradually disappears from official sales channels. Chips may continue to be available through online auction and retailers for years after the fact but, officially, the products are replaced by their successors, or they just disappear if the consumer base loses interest. Starting September (2012), Intel's Sandy Bridge series of central processing units will embark on their final journey, so to speak. Currently, Ivy Bridge CPUs are still about $100 / 80-100 Euro more expensive than their Sandy Bridge counterparts.
As such, SB-based systems and standalone CPUs are still shipping. There is also the matter of 22nm-based Ivy Bridge not having yet spread to all corners of the world. The initial, high-end units may have been around for a while now, but the dual-core and quad-core versions only just came out. Same goes for the laptop parts and the Ultrabook units. Granted, Intel is shipping third-generation processors to OEMs as we speak, but system sales will only take off after June 24. All in all, by the time September rolls around, Ivy Bridge prices should lower to SB levels and the world will be ready for a new wave of PC replacements. The timing is actually quite well planned, being the back-to-school season when many people go on shopping sprees.
It will be interesting to see how sales of Intel CPUs compare to those of AMD's latest Accelerated Processing Units, although it is unfortunate that a competition of this sort will be limited to notebook front for a while (the desktop Trinity collection was delayed to October, last we heard).