Well here's my report on the situation. I've seen two 60GB PS3s in the wild, at Best Buy and K-mart respectively, and one 20GB PS3 in the wild at Target. All three were on the shelf, ready to be sold to any passerbyer. I have not yet seen a Wii anywhere.
Going on a complete hunch this is what I personally make of it. The Wii has a high demand, but I'm betting Nintendo didn't meet the shipment numbers they wanted. Places like Target and Walmart around here were getting a pathetic amount of Wii's in while Best Buy was the only store with a regular shipment (they had 12 each sunday, which still seems pretty low, to me anyways...). So my verdict on Wii is that it's popular, but just how popular is yet to be seen because I think supply has been an issue.
As for PS3, it's rare to see a console this close to a systems launch readily available for purchase. I'd expect there could be a variety of reasons though, and first and foremost I point to the price. Whether or not the PS3 is a "good deal" for what's in the box, it's still a shit ton of money for most consumers. I don't think people are willing to shell out 500-600 dollars for a console simply because it's there, on the shelf, waiting to be sold. I personally plan to get a PS3 for FFXIII alone, but like a lot of other consumers, plan on waiting til the damn thing is cheaper. I have next to no interest in blue ray, and don't even foresee myself with an HDTV for at least two more years. Besides price, the PS3 is getting a lot of bad press from mainstream media, and ebay prices are down, so scalpers would have no interest in it anymore.
Of course, this could mean that Sony shipped a lot more than we expect, but my hunch says they didn't.