Perhaps he has. But the investigation has moved on to bigger and better things.
Though the MSM has been loathe to admit it -- this article being a prime example -- the scope of this grand jury investigation goes far beyond the Plame Affair.
The GJ is actually investigating the entire nexus of unauthorized leaks from and about the CIA, many of which had national security implications.
The media is not thrilled by this development, as they have assiduously cultivated these leaks in order to serve their anti-Bush political agenda. Thus, we see the odd situation where the media is keeping their reporting low-key and practicing damage control over a "freedom of the press" issue they would normally be screaming from the rooftops.
NYTimes and such have tried to paint the investigation as just about "Plame" and just about "Novak" as if they received the leak nothing was wrong unless they printed it.
Then there's the Newsday intelligence leak, and the State or Cia memo leak later, probably by the Admin, confirming Wilson's wife recommended, suggested, whatever, her hubby for the Niger job.
I believe that is the key to this story: that this is not simply a "leak of the Plame name" investigation, but rather involves the whole bloody operation of the Old Media Fraudcasters when it comes to their revealing high secrets on the United States.