Towards a crisis caused by a “lack of foresight” in the United States?

Since the mid-1980s, the United States has had an abnormally low savings rate and a chronic external deficit, and has therefore accumulated significant external debt. The capital accumulated in the United States is therefore counterbalanced by this large external debt. We can talk about the United States’ " lack of foresight ” : Population ageing, which will take place, is likely to accentuate the decline in the savings rate and lead to a very high level of external debt. Countries should normally accumulate external assets in anticipation of ageing; The United States avoids a serious crisis caused by the external debt only because of the dollar’s reserve currency role, which may be fragile in the future if the United States’ financial situation deteriorates, or if other reserve currencies appear.