Tyro offers some background on the development of the telephone:
Bell got involved in developing the telephone because his wife was deaf and he was interested if the technology could help deaf people.
In any case, the telephone is an intesting case-- the more people have a telephone, the more valuable that an individual telephone becomes linearly and more valuable the entire system becomes, quadratically (Metcalfe's Law-- look it up). As a consequence, for the public good, the government decided to support policies that would spread access to telephone service to as many people as humanly possible in the USA, even if they were geographically isolated. It is a great example of a good that creates a lot of public value, and ensuring universal access was done precisely to support the public good.
According to Wikipedia, "Metcalfe's law states that the value of a telecommunications network is proportional to the square of the number of users of the system."
