Well people who don't play games really aren't going to buy a PS3. I mean it's sold as a game console and people aren't going to add a game console to their high end home theatre. For some people, getting a PS3 does make sense, but I can tell you that people who really love their home theatres, they are going to get a dedicated blu-ray player. And the fact that the PS3 can't do internal audio decoding is a turn off for some people (for some reason, I don't really understand it, but some people want internal decoding).
Saying that, I bought a dedicated blu-ray player for probably more than I could have got a PS3 for. When it comes to home theatre equipment, I just like to know that each piece was designed specifically for a task to be the best at doing that task. I know the PS3 probably does a nice job, but it's probably more of a mental peace of mind thing.