I was unaware of Revolution's release date. Nonetheless, I still believe they have the right position. If they can keep the PS3 buzz at full volume, they can squelch Revolution's introduction, and first-mover advantage is in Sony's court. I recall seeing a report that Revolution would only have 400k units availiable, rather than the 1M figure I heard in the past. That gives Sony an opening to hold on to prospects who would go with either unit, since there won't be a massive supply of Revolutions to draw them away.
And yes, Sony would rather sell out at a lower number for a duration than at a higher number for a short period. They can say "look, we're still selling out weeks after release, despite the competition, because we're the best!" This is not an issue of profit and sales today, it's an issue of marketing. Consoles are cash cows that you milk steadily for a couple years by selling games, not here-today-gone-tomorrow flash in the pans that pay for themselves and pay for the here-tomorrow product that replaces them.