Magis Networks, a developer of chipsets designed to allow users to network home electronics, filed for bankruptcy protection in mid-December: In 2002, the company raised $48 million from big shots including Motorola, Time Warner, Panasonic, and Sanyo. One analyst cited here says the demand for networking home electronics didn't materialize. He can't imagine why he'd want to hook his PC to anything. I can! I think a lot of people would like to stream music from their PC to their stereo.
Still, there may be something to the fact that perhaps the market isn't ready yet. One reason may be that the higher speed wireless networks haven't made major headway into the home yet and higher speed is required to steam video, for example, from the Internet to a TV. I imagine the general public also sees connecting multiple home electronics as a pretty complicated undertaking. Until it's faster and simpler, this market space might be slow to take off.