Courtesy of Kotaku, who first noticed it, Sony has given people a clue as to why PS2-backwards compatibility remains elusive to all but the earliest of PS3-adopters. Though early cost-cutting measures clearly motivated the initial removal of the necessary chips for the original hardware-based PS2 emulation from the PS3, Microsoft's Xbox 360 has had rather good results with software emulation of Xbox title for the Xbox 360. If Sony wanted to put PS2 emulation on the PS3, they could do it. Why they haven't has been a question on my mind for quite some time, though I chalked it up to Sony's eccentric management style.
Well-constructed 'HD' collections like the God of War Collection or the The Sly Collection are clear money-makers for Sony, so leaving PS2 emulation 'dead' does make some financial sense from that angle - but the library of quality games for the PS2 far exceeds the number of HD remakes that will ever be released. Sony's not stupid, though, when it comes to hanging onto the PS2. The hardware is quite profitable and people are buying it. Though it retails for only $99, the parts have been manufactured for so long now (10+ years total, 6+ years for the slim model) that the cost to Sony has to be rather negligible. Not to mention it continues to sell 6 million units a year with only a slight drop between 2009 and 2010.
With the catalog already established, and people still buying consoles, Sony has no real incentive to re-introduce backwards compatibility into the PS3. Value-added collections like those cited above are important, but before seeing the consistent 1+ million per quarter figures for the hardware, it mystified me as a gamer why Sony was hanging onto the hardware. Sony is essentially saying, 'until you stop buying PS2s, we're going to keep doing what we're doing'.
Some of the 6 million yearly sales can be attributed to replacing failed units, but translating that against the current install based would equate to 4 percent failure per year. Given the age of the platform, most PS2s see light duty compared the current generation of consoles, but even that point is irrelevant. Sony doesn't care why people buy it - as long as they keep doing so. They're even using PS2 hardware in new devices like the BRAVIA KDL-22PX300, a 22-inch T.V. sold (at least for a time) in the U.K. with a PS2 integrated into the stand.
The continued success puts the PS2 further in the lead as the best-selling console of all-time, at 151+ million units.