I think it’s a combination of different issues: Governments have failed because they don't even promote healthier options. There are many myths surrounding nutrition, such as the belief that refined vegetable oils are better than butter or that low-fat diets are preferable. People often lack interest in learning about nutrition or simply rely on companies and governments for guidance. Additionally, the current lifestyle heavily promotes fast food consumption.
Food companies bear no responsibility when offering unhealthy products. They simply comply with food regulations while focusing on creating products that are highly addictive and in high demand, prioritizing profits over public health.
I also believe there is a cultural gap related to gastronomy and food. In countries like Spain, Italy, France or Japan, people tend to value traditional cuisines and fresh ingredients, which are generally healthier than the ultra-processed foods often favored in places like America.