At this point they exist.
Timeline is looking similar to the original xbox launch.
Sony and MS seem to have diametrically opposed philosophies on this one, Sony push out very expensive early devkits in tiny numbers, MS ships a software platform to a large number of devs and waits until they can produce enough devkits to get them out in numbers.
Both have their plus points, personally I'd prefer a combination of both.
I think MS's real failure in this department is not getting closer to final kits to key developers in time for E3 (same thing happened with Xbox).
If they don't have a truly horrible E3 I doubt it will matter in the long run.