“The plain and simple fact is that they’re too busy or too important to talk to us,” he said.

that is probably exactly it. there is a new way of living and most Americans are not yet part of it.

I love that Quora has answers to the meaning of life* but not an answer to what Quora's phone number is.

* See: http://www.quora.com/Meaning-of-Life

I guess it is not a practical medium of communication for companies that deal with a large number of free users.

You got it. Very impractical to have potentially millions of free users call.