If there is no US debt, implying no need for Treasury bonds, that means there's nothing as clearly stable as Treasury bonds for people to invest in?
The way you "fixed" the quote is patently untrue. IBM one month commercial paper is much more stable than a Treasury bond (note the term bond means maturity greater than 10 years).
Sure IBM has minutely more credit risk, but the interest rate risk (duration) of the Treasury bond far exceeds the IBM paper. Thus, the Treasury bond is a much more unstable (risky) security.
You could then say, well a Treasury is more stable than any security of the same maturity. I would also say that is effectively untrue. A Treasury bond has no default risk, but only because we assume the Fed would print money to enable the Treasury to make the interest payments. But if the Fed does that we get high inflation which is the very definition of economic instability. So buying a Treasury can only be said to be stable with respect to securities in the denominated in the same currency .
A much safer option would be to buy corporate bonds denominated in many currencies, e.g. buy a Toyota bond in yen, an Rio Tinto one in British pounds and maybe Aussie dollars, a Vale in Brazilian reals, etc. This way you would have marginally more credit risk, but you've diversified away not only the risk the dollar will lose its value, but also risk of a single country's economic growth slowing, thereby lowering total risk.
Lastly, you could say that there are not enough of these corporate bonds. Well that may be because government issues crowd out the market. Companies may borrow more and grow if the US government wasn't demanding $1 trillion per year in funds.
In sum, the underlying article, and analysis, are unimaginative at best.