And I would add that the answer to the headline question is the same as to why Hillary Clinton(D) is still not in prison for her eggregious violations of the espionage act.
From Angelo Codevilla at American Greatness: "Incontrovertibly, the officials who gave these stories to the Times and Post violated the Comint Statute, and are subject to the “10 and 10” for each count. There is no clearer instance of what the governing law is, of how it was violated, and of the punishment that this incurs...
Nor is there any doubt as to who at least two of these “senior intelligence officials” are: Former CIA director John Brennan and former Director of National Intelligence James Clapper.
Beginning in January 2017, Brennan and Clapper made essentially the same statements on national television. The only possible excuse — that their allegations were lies — is irrelevant because the essence of the violation is the revelation that U.S intelligence was monitoring the communications of the Russians in America, and those of the Trump campaign as well. This is true, and that revelation is a textbook violation of the Comint Statute."
The old saw about 'the wheels of justice grind slow' should be remembered in this regard. Of course, that old saw could rust to dust, so who knows?
However, there is a new Sheriff in town, so to speak, in the person of US AG Bill Barr who testified before Congress last month. He plainly understated, "Spying On A Political Campaign Is A Big Deal." Leftist outrage erupted afterward as they fell to their fainting couches in response.
The question is a good one: Why Are Clapper and Brennan Not in Jail? And I would add that the answer to the headline question is now 'the wheels of justice grind slow.'