The chicken and egg problem that all new technologies must overcome. The problem is that no one wants to be the first person to adopt a new technology. This problemlem plagues almost every new product but is especially difficult for technotoys to overcome due to combatability issues and the fact that most involve interaction with other similar technologies.
If there is no market for a device, then companies are less likely to develop products and services for such a device. If there are no products or services, then people are less likely to buy the devices, shrinking the market even more.
The cannonical example is the videophone. A staple item in science fiction and often predicted by futurists to be only a matter of years away, the technolgy to make these devices cheap and efficent has existed for the past decade. However, no one uses them. Why? No one wants to be ther first person to own a videophone because it would be nothing more than a really expensive telephone until everyone else bought one too.
Television is a good counter-example, demonstrating that a quality product can overcome the adoption problem, as are telephones and the World Wide Web.