I think you give them far more credit than they deserve. Remember that John Walker guy who sold Russians every secret he could get his hands and did it for over 10 years. Or Aldrech Ames who got away with similar stuff inside the CIA for even longer. And then Hansen at the FBI. Those guys all held top secret + clearances and got away with spying for the Russians for years and years and none of them were very careful how they did it. They all lived well beyond their means.
but dimentia does not go undetected in the intelligence community.
“Ever hear of rapid onset or ‘sudden’ dementia?”
The coroner ruled his death a homicide.