For starters, I mean obviously the demand for something like the Wii is going to be higher than the PS3 right now just because it's rediculously cheap in comparison, but about whether there really is no demand for the PS3 or if they're just doing a good job making them, I wouldn't be surprised if it's a little of both. When I bought my PS3, it was the last one at the local EB. The next day, they had another shipment in. To anyone who didn't know better (say only goes in once every few weeks) it probably would have looked like they didn't sell any.
As for that info on units sold, it's most likely a month old at least (slightly more official sources haven't even gotten the January sales numbers out as far as I know), so considering that's about two months of PS3 sales, that's actually not that bad, and on pace to just about hit where the 360 was after a years time. With a price drop, you'll more than likely see sales pick up even more. Yeah the Wii numbers are pretty impressive right now in comparison, but anyone who didn't expect the Wii to outsell two consoles that are substantially more expensive has been living under a rock since the dawn of commerce. None of this means Sony's actually in trouble. In fact, if anyone bothered to pay attention to the games coming to the console rather than just the price tag (which will go down over time), they'd probably start to realize the PS3 is going to be a great system to own, just like all the others.