Some people ask where I get my figures. For the most part, they come from the government itself. Other references are linked in this article. Some of it, yes. For example, if you buy a U.S. Savings Bond, or if the retirement fund you're in invests in government paper, you own some of it.
Many businesses own government debt.
Foreign countries and businesses also own it. If the government defaults, you lose the money owed you. So do all those other businesses and governments. The global economy collapses. Since that's not an acceptable alternative, the government must continually borrow more, and more, and more, to pay the debt it already owes.