Yes, that would be the source of a delay...
Game developers work around multiple architectures and memory systems, between consoles and PCs,
so such a delay would certainly mean a 1 year delay, but not necessarily the end of the world,
except that basic market analysis would show that Sony having a head-start would be disaster for MS,
given Sony's global demand let them come behind vs. MS initial head start (and horrible PS3 launch).
So perhaps they thought about it for a moment, but those factors would immediately rule out such a move.







