> People who work on Twitter, who have built a large following, who use Twitter to propagate messages, to network with peers, and to learn facts and rumors, would pay not just $4/month but $4000. Whatever the price Twitter would charge journalists, they would gladly pay; it's a cost of doing business.

No they wouldn't pay $4000 a month, you vastly over-estimate the willingness of users to pay for social media. Any paid social media was a complete failure. Twitter customers are the advertisers and data hoarders, not the people who tweet.