What you want to do is make something that people want so much that they'll use it even early. So e.g. writing a Basic interpreter was the right thing in 1975, because microcomputer users were programmers, and the alternative was programming in machine language. Whereoscope is roughly the equivalent thing for this market. Parents really want to know where their kids are, so even though there may only be a few families that have the right hardware already, there will be enough users to keep Whereoscope afloat till more do.