One of the things that disillusioned him was when he went to the Soviet Union, he thought he'd get some cushy postion.
Instead, he was given some boring job in the middle of nowhere.
When he returned to the States, he then turned to Cuba as his Marxist "paradise".
He thought the Soviets weren't doing Marxism "correctly", but somehow Castro was.
He wasn't paid much, EVER.
He and Marina lived in a dump.
All he had to his name when he died was some paltry amount of money and his guns.
He left some $ for his family, in addition to his wedding ring.
Marina left him, and he had nothing left to lose, especially after Cuba refused his passport request.
If he was ever "paid off" by conspirators, he never showed evidence of it.
It seems Oswald did live a bit of a charmed life in the USSR. He was given a very nice apartment, far and above what the ordinary Soviet worker had for living quarters. His job was not glamorous, but neither was it arduous. He had a very full social schedule and was a bit of a minor celebrity. Epstein hints that it was intelligence delivered by Oswald that enabled the Soviets to shoot down the Powers U2 ... as monitoring those flights had been his job with the Marines in Japan. He married Marina, whose father was a high-ranking officer in the Border Guards section of the KGB. To imagine this alone escaped official KGB scrutiny is just plain stupid.
The Soviets sent over a fake (IMNVHO) defector, Nosenko, to try and convince our intelligence services that the Soviets had "no interest in the kook Oswald." In those days, every foreigner, whether it was Oswald, Bill clinton, or Richard Holbrooke, in the USSR had a cadre of KGB minders. To attempt to deny that is insultingly disingenuous. Fatuous.
Yeah, I suspect Epstein is or was a CIA 'Contract Author,' but the book is undoubtedly worthy of consideration. Discount neither the Soviets nor the Cubans. The Cuban DGI was (or is) a highly sophisticated intelligence group that was trained and operated under the aegis of the Soviet KGB and handled and trained by the 'STASI' the secret intelligence agency of East Germany, the DDR. The Cubans were good at it, and had succeeded in placing agents very high up in the CIA. Remember also that JFK and RFK, when they weren't dallying with Marilyn Monroe or Momo Giancana's girlfriend, were up to their eyeballs in plots to assassinate Castro. Perhaps he somehow turned the tables on them!
In the meantime, we are still working on the mechanics of the hit. We're close to the "How." The "Why," and the "Who, remain fogged in.