Let me answer the subtitle in the first sentence, yes ATI did help with the first DX10 "the way its meant to be played" title to come out, but only indirectly.
As we noticed this weekend, Lost planet is an Xbox 360 clone and the Xbox 360 is powered by ATI's Xenos chip that can also be called R500. This chip doesn’t differs that much from the R600 except it is slower, cooler and has embedded memory, but functionality wise both chips can cope with DirectX 10 and Unified Shaders and the rest.
This also means that if ATI invests some time in R600 driver optimisation, the Lost planet might end up running very fast on the R600 marchitecture, but this is so far only a theory.
At least this one good thing about consoles getting more powerful, but we still can not forgive the fact that Call of Duty 3 was console only game.