This slashdot article covers this news article which describes a hackers success at breaking through the PS3 hypervisor protection layers to get full hardware access. A few of the slashdot posts describe why people may want full PS3 hardware access, and why Sony may be keeping the full platform access away from the user.
To be perfectly honest, I'd pay extra for a PS3 (and XBox 360 too!) which was unlocked for software that I've written myself, and it wouldn't be used to run pirated games. I'm sure others feel the same way. I'd love to see more hardware manufacturers do this.
Sigh, I can but only dream. :)