Snowden broke the Snowden story. Greenwald was one of the people who he chose to send it to, but Greenwald pretty much had it handed to him. He definitely has value because he covers how incredibly ideologically motivated the press is in it's operation, and probably has extra insight into it because he was part of it earlier in his career when he worked at the Guardian and then the Intercept, but the Snowden thing was about him being in the right place at the right time.