The USA has great linguistic resources; however, they have always been ignored or even destroyed. The USA is predominantly a monolingual English-speaking country. The majority of the immigrants do not speak their native languages past two generations.
Indigenous languages of Native Americans disappear as fewer and fewer speakers of those languages continue using them in their daily activities. There are very few people in this country who are trying to learn non-English languages and even fewer who actually succeed in doing so. All these things happen because in the United States multilingualism is not receiving a proper support from the majority of the population and state/federal government.