This is one of the biggest issues with US' private healthcare system.
The U.S. government just doesn't feel that direct "cost" in the same way countries that have to pay to fix the health of their citizens do. This is why you see a lot of other countries put higher taxes on sugar, gasoline, diesel, etc. Because they see a direct correlation between the consumption of those things and them having to invest more in their national healthcare system out of their tax money.
Meanwhile, in the US, since it's the citizens that pay out of pocket, that money still goes into the economy, so it's kind of all the same to the government whether or not they get sick or not. They may notice some correlation in the long-term, but the negative effects of these things are not nearly as urgent to the government.