Look it's hard to put a definite date on it, because capitalism didn't just happen in one day. It happened over centuries. The european alliance had its roots in the colonial rush for the New World, and later Africa. After squabbling over territories, they learned they could make more money by cooperating and exploiting the poor countries together. And it's been like that ever since about 1900.
Let's see literally any one of those countries try to go socialist and see how long it takes for the US to invade and coup them.
That's debatable, but you haven't answered the question.
Look it's hard to put a definite date on it, because capitalism didn't just happen in one day. It happened over centuries. The european alliance had its roots in the colonial rush for the New World, and later Africa. After squabbling over territories, they learned they could make more money by cooperating and exploiting the poor countries together. And it's been like that ever since about 1900.