The Saturn launch was changed by a very long time margin. A week difference is not going to have the same effect.
It wasn't the early release that pissed off retailers. It was the lack of units certain retailers got. Only the biggest of chains received Saturns for the first several months (TRU, Target, Walmart). Even those who got it had to rush to allocate purchasing funds and shelf space (retailers like to plan ahead for these things). I agree that an early Xbox release has nothing in common with the Saturn debacle.
Sega's slow death began the day they announced the early release at E3.