The shortest commercially available submarine cable between the US and Sao Paulo alone is significantly higher than that (almost double), and it comes out of the east coast, so you'd still have to factor in the latency between Chicago and New York.
Even specialized low latency networks that mix wireless and fiber will still have much higher latency than the radio.
The tradeoff is that shortwave radio has very little bandwidth so you're restricted to simple signals.
If you take one of the routes in the article, Chicago to Sao Paulo.
The distance is about 8,400km in a straight line.
According to https://en.wikipedia.org/wiki/Skywave a single shortwave hop can reach 3,500km, so 3 hops are required, or about 30ms.
The shortest commercially available submarine cable between the US and Sao Paulo alone is significantly higher than that (almost double), and it comes out of the east coast, so you'd still have to factor in the latency between Chicago and New York.
Even specialized low latency networks that mix wireless and fiber will still have much higher latency than the radio.
The tradeoff is that shortwave radio has very little bandwidth so you're restricted to simple signals.