I don't think that the food industry can be let off the hook so easily. There's no doubt that being unhealthy is much easier than it used to be: unhealthy food is cheap, convenient, and superficially appealing. Back in the day, you had no option but to cook a meal from scratch using raw ingredients.
But even supposedly healthy food is not what it seems: battery-bred chicken has far higher levels of fat than proper organic free-range, and fruit & veg are often far from fresh, meaning that nutrients have degraded.
So we're asking the public to spend more money and time in order to cut obesity - a tough sell.