The article simply mentions the idea of economic collapse. It doesn't talk about the mechanism.
There are two ways that governments have "collapsed" their debt. The most common is to inflate it out. This is the current strategy of the US.
The other way is to default on the debt. That is a common solution. Anybody still have Tsarist Russian bonds? Right after the revolution, those were defaulted on and that was part of the reason why some western powers were trying to overthrow the revolution and bring back a government that would continue to pay on those bonds. I found a table listing the number of countries that defaulted on their bonds.
1820-1840 15 countries 1870-1885 17 countries 1930-1949 25 countries 1980-1985 33 countries
So, will the US ever default on a sovereign bond? There are people taking bets on that and last year, the odds were going up.If we do not default, we will face a period of time of recession - very likely to be a number of years long.