The dynamics of international trade has changed A LOT in those 70 years. Back then we were a manufacturing powerhouse, now we are little more than a pay piggy for several continents full of welfare queens. We need some drastic adjustments if we are going to stay in that top spot.
We aren't broke because of USAID.
US bonds are a historically strong investment. There's a reason we are a global economic force despite our debt, and it's the same reason China owns so much of our debt, and it's their investment in US bonds.
Our current predicament is due to a large influx of money printing and low interest due to covid policy, followed by interest hikes that slowed down borrowing, and limited public works project capability due to supply line shortages.
I am indifferent towards cutting funding for Ukraine and other USAID projects. A certain amount of fiscal conservatism during economic strife is probably a good thing. As you said, we are not a manufacturing powerhouse, but we are a very strong consumer market. We don't export enough goods to strong arm the world into paying us for importing their goods.
Market confidence directly correlates with consumer spending, which is the foundation of our economy. I'd love to see the markets rebound, I love a good economy no matter who's in office, but the optics aren't good right now at this very moment.