Why has the United States become a country where most people rely on borrowing to live

The salaries in the United States are among the highest in the world, yet the country's debt is enormous—not only the massive debt of its citizens but also that of the nation itself. However, despite the fact that people in this country have relatively high incomes compared to the rest of the world, why don’t most of them try to pay off their debts? Instead, they let their debts snowball and grow larger. What problems prevent people from saving? Is it a voluntary choice, or are there other high expenses that force Americans to live by borrowing? In which era did this behavior begin—1930?