This is a great question. Socialization is a huge part of the creation and sustaining social inequality. The person that has done the most work in this area is Pierre Bourdieu. He is hard to read, but he offers some of the most insightful points about society and the inequalities that are present.
The social theories of Pierre Bourdieu emphasizes something called cultural capital. Cultural capital, in brief, is whatever gives a person the ability to succeed. Much of this cultural capital is passed down from one generation to another. For example, if a person speaks very well, it is most likely because that person has grown up in a household where such things were common. That is just the way people speak.
This fact, in turn, allows that individual to have a leg up in the upper echelons of society, where thing like speech matters. The same goes for tastes in art, music, fine foods, dress, etiquette, and education. The more cultural capital a person has, the greater the chance for success. In this sense, people of a certain social order have inherited a huge benefit just by their birth, a point that is often ignored or conveniently forgotten.
All of this shows that socializing agents have a profound role in success and failure. Moreover, when we add to the mix that not all cultures are emphasized to the same degree, then those of a different culture start with a great handicap. In short, socialization makes a very big difference.