One thing that can happen is a game developed later ends up working with an improved engine, and graphics are tweaked and updated and improved. I believe Dirt on the PS3 is supposed to be an upgrade over Dirt on the 360, for example. In the case of Virtua Fighter on the 360, its graphics were updated over the PS3 version. Bioshock saw spots also where that is similar. Same with Oblivion regarding the PS3 vs the 360 version.
The PS3 and 360 are in the same CLASS graphically. Why people expect there not to have this happen is absurd.







