Curious to hear why you think that is? The truth is that a local currency is almost always dependent on inflation to keep its value - that is why people would not accept UST at a low rate, they will want higher rates to justify the higher inflation - and the US does NOT have an inflation problem, nor does most of the developed world. In fact, it is quite the opposite. This is probably the most important issue here that people are saying will happen - a hyper-inflationary spiral which kills the USD. I think we should talk more about this because it is pretty important!
Well, yes, the US
does have an inflation problem, but that's not the main problem or even a particularly important one in the grand scheme of things. In particular, I don't believe the US dollar is going to go the way of the Zimbabwe dollar, like some people here think. Inflation alone is almost certainly
not going to be what kills the US dollar.
As long as the rest of the world believes that our government can tax citizens and pay interest on its debt, the international community will have a demand for dollars. Demand for dollars is not only buying and selling of goods - most of the time it is transfer of US Treasurys, which act as cash equivalents. So if people think they will get paid back on their UST, they will have no problem dealing with the US and holding our debt. And this payments, we agree, will always be made.
And
here is the problem. There are growing indications that the rest of the world does
not think that, and other powerful countires (notably China) are trying to move away from the US dollar as a reserve currency. This is not unexpected - no currency has remained a reserve currency for much more than a century - and it's certainly not going to come without warning, but it's definitely going undermine the value of the US dollar and radically impact the US economy. Will there be a recession? Very probably. Will the US recover? Again, probably. Will there be an apocolypse? Highly doubtful.
In the past countries "blow up their FX" because their economy relies too much on one product - like oil and Russia or agriculture and Argentina in the mid 1900s or Venezuela today - or rely too much on foreign capital flows to operate - like many countries during the Asian Currency Crisis of 1997/1998. The US does not have this problem. If you think the USD will collapse, I assume you think that many many other countries will have gone down first, since the USD is the most stable, liquid and widely accepted form of payment in the world (again payments are usually in UST, not dollars for candy bars, on aggregate).
Certainly, many other countries will undergo economic collapse before the US. This appears to be already happening.