Tracy,

Check out http://www.ubiquisys.com , including the list of partners. These guys are trying to drive data, voice and application convergence towards a single personal device, and it's already well advanced. The only potential impediment I can see is future consumer alarm about the increasing levels of electromagnetic radiation in the home. One of those stations creates ten times as much EMR as a dect portable phone. It's still small, but some people are claiming that all these radiating devices in the home are the modern equivalent of the Romans' use of lead for water pipes. ;-) Whether true or not, that sort of idea could easily achieve prominence in consumers' minds which could change things completely. See links like http://www.dirtyelectricity.ca/Way%20to%20avoid%20EMF%20exposure.htm for an example of the sort of thinking that could become prevalent.

FWIW, "somebody I know very well who has a scientific background" has recently spent thousands of $ installing 5km of data cable in his house so that no wireless is required. Every room has at least 4 data ports. There's also a computerized lighting system to avoid mains wiring above knee height in walls and the switchboard is about to be encased in a Faraday's cage. At first people thought it was a bit funny but you'd be surprised how many of his equally smart friends are now reconsidering their wireless routers.