The entire Federal Government has been captured by the Left, and is not staffed, top to bottom with the little Marxist robots that colleges turn out by the millions each year.
Another factor, I think, is that people on the right, who might have thought of joining the FBI or CIA upon graduation in, say 1960 or 1970 or even 1980 - have, if they have graduated since then - been through a very different experience.
The Government used to belong to all Americans. But since around 1980 Conservatives have increasingly seen where the Government is an active agent of hostility against them. Hell, white kids have had to overcome racist anti-white quotas ("affirmative action") since around then just to get a place in college.
Plus Conservatism drank deeply from the libertarian fountain beginning around 1980 - so the private sector is more the natural home for anyone with "rightest" tendencies, and the Cathedral (to use Heartiste's term) the place for leftists.
The right's alienation from Government has been a big factor in the leftist's takeover.
I will never forget that the greatest anti-communist the CIA ever employed, James J. Angleton, was sure that the CIA had been deeply penetrated by Soviet Communists for the last decade of his career.
As the head of Counter Intelligence he led the hunt for the high level mole or moles within the agency, the hunt which loosely inspired John Le'Carre's most famous trilogy: The Quest for Karla.
Angleton resigned on Christmas Eve, 1974. Essentially due to a PR scandal concocted by the ever-willing Seymour Hersch.
Angleton told reporters from United Press International that he was quitting after 31 years because "my usefulness has ended" and the CIA was getting involved in "police state activities."
So, I date the fall of the CIA to his departure.
The mole that Angleton sought was never exposed.
Three of Angleton's senior aides in counter-intelligence—his deputy Raymond Rocca, executive officer of the counter-intelligence division William J. Hood, and Angleton's chief of operations Newton S. Miller—were coaxed into retirement within a week of Angleton's resignation after it was made clear that they would be transferred elsewhere in the agency rather than promoted, and the counter-intelligence staff was reduced from 300 to 80 people in 1975.Source: Wikipedia
A year later DirectoryColby himself would be ousted, to be replaced by George H.W. Bush.
In 1996 Colby died in an strange canoe accident, drowning on the small river he lived on.