Anyone who wants a system that does more will buy a PC. The PS3 is built around a gaming console so it will never function adequately as a PC. Not to mention it wouldn't be compatible with anything on a PC. Those interested in a home theater want dedicated hardware. They don't want audio/visual performance compromised. So ultimately, while for what the PS3 offers it might not be a bad price, it's perceived by everyone as a game console. And in that regard it is overpriced.
I will never understand this kind of reasoning... because it can play games it'll never function adequately as a PC? Because it's not a 1 function piece of home theater hardware its a/v performance is compromised? What are you talking about man? It's a computer, pure and simple. It may have been purposed to play games, but ultimately it's a computer, and that means it can do a ton of different things, only the software decides what its limits are. It would make an awesome computer or home media center device, they've just chosen to cripple it because they're Sony, with all the short-sightedness that entails.