A correction on terminology might prove enlightening. The US citizens working for the CIA are “spies”, handlers, or agents. Anyone who works for them, eg provides information, is an asset. They're not an employee, advisor, or “spy.” Theyre an asset to be used to the benefit of the United States as long as theyre useful.
That said your point on trust and incentive doesnt hold up to history. Being an asset and providing information to another country almost always ends in prison, or death, or best case exile. The material rewards are laughably small, thousands of dollars typically. And yet agents, of all nations, are good at their job and consistently succeed in recruiting new assets.
That said your point on trust and incentive doesnt hold up to history. Being an asset and providing information to another country almost always ends in prison, or death, or best case exile. The material rewards are laughably small, thousands of dollars typically. And yet agents, of all nations, are good at their job and consistently succeed in recruiting new assets.