I think you're analyzing it as "[never goes off] and [assassinates him]", when the OP meant "never [goes off and assassinates him]".
"Goes off and assassinates" is just an idiomatic expression signifying essentially the same thing as "assassinates".
Ah!
Thank you. I clearly had a mental misfire.
In either case, Malcom X would have essentially split the Nation of Islam down the middle.
After returning from his Hajj to Mecca, Malcom was essentially a moderate Muslim, shunning the radical rhetoric and corruption of the Nation.
Had he continue to operate his Mosque in NY, a major schism would have resulted.
Between the moderates and the radicals, many who joined the nation were actually spiritually committed Muslims who saw Malcom X as more of a spiritual sheik, over a political leader.
This was incredibly dangerous for the Nation and Elijah Muhammed who at the time cultivated incredible political and financial power through a near ideological monopoly of Black Muslims in the major urban centers of the United States.
Though if he weren't to be assassinated by the Nation even with these threats, I don't see anyone else actually doing so.
The only people he pissed off was the Nation. Unlike MLK, who pissed off the KKK, Local Southern PDs, Segregationalists, Federal Gov., Malcom X was just a firery rabble rouser rather than a a real revolutionary who saught actual political change.
He probably survives as a famous NY Imam, as his national fame slowly fades.
He may take up MLKs cause but in doing so would make him target number 1. Even still, a civil rights movement with Islam as the main spiritual theme would be extremely difficult to do, especially if the religious rhetoric by Malcom up this point was one of exclusion rather than inclusion.