Kotaku obtained an internal GameStop communication detailing the new "K" model of PS3 hardware, which states that an HDMI cable will now be required to display high-definition, and that component cables will no longer work. GameStop doesn't quite have all the details right, but part of that is true.
"The new CECH-3000 series PS3 requires HDMI only for BD movie output in HD, in compliance with AACS standards," Sony told Ars Technica. "PS3 continues to support component output for HD gaming and streaming content." The restriction is just on high-definition video from Blu-Ray discs. So this isn't a cost-cutting measure like the removal of PS2 hardware -- it's to conform to the Advanced Access Content System, a standard for DRM developed by a consortium of media companies including ... Sony. The standard requires that devices restrict analog outputs to 960 x 540 to prevent recording from analog capture devices.
The strange part, then, is that the PS3 ever supported HD Blu-ray playback through component. Digital Foundry speculates that the rule didn't kick in officially until the AACS Final Adopter Agreement in December 2010, and thus only affects PS3s produced after then. That would mean that Sony (and pretty much every other electronics company) skirted its own rule for as long as possible.