The main reason cold calling is dead is the ever-increasing level of sales resistance in today's world. Of course nothing triggers sales resistance more than cold calling!
The latest bit of evidence that people are sick and tired of sales pitches is the decision by the Loews movie theatre chain to begin publishing the real times movies will start. In other words, people are fed up with showing up at the published time, then sitting through 15 minutes of commercials before actually getting to the movie they came to see. So, in response to the frustration, Loews is going to start telling the truth about when the movie really starts, and it's up to you to come 15 minutes early for the commercials.
I'm astounded that people continue to challenge the idea that cold calling is dead when the sales resistance backlash continues to surge in today's society.