I think that Marilyn let her fantasies control her perceptions too much. This isn’t politically correct, but back then, as is quite a bit now still, if you are an actress, people will think of you as a sex object, not a person to get to know for your mind. Back then, it was doubly reinforced. The Kennedy men all married for social prominence and ambition and had showgirls and actresses on the side. Prominent men didn’t marry them or leave their wives for them.
I don’t know if you know this, but Dorothy Dandridge, the first black woman to be nominated for an academy award, was wooed by a wealthy Argentine banker. Dorothy had fantasies of marriage, but the banker was married and wanted to keep her as his mistress, “concubina” in Spanish. He said to her (Dorothy) that to marry an actress would ruin his professional and social standing. Say the least that he was already married.
I think that IF they did bump her off, it was because of that phone call she made to Jackie, threatening to break up the marriage or something. Either that or threatening Jackie herself. But I personally believe that Marilyn simply self destructed and couldn’t live with herself in the end. Couldn’t live with facing reality. She was on a downward spiral for a long time I think.
A gentle correction, if I may. Dorothy was the first black woman to be nominated for the Oscar for Best Actress, not for an Academy Award period. Dorothy was nominated for 'Carmen Jones,' released in 1955.
However, the great Hattie McDaniel was the first black person of either sex to WIN an Academy Award -- Best Supporting Actress for her classic role as Mammy in 'Gone With The Wind' (1939).