My guess is that it has something to do with the government tariffs on sugar imports. As Americans, we all pay way more for our sugar than the rest of the world does. The sugar industry spends a bunch of money lobbying congress to keep it that way. Someone ought to start a lobby group for the sugar consumers of America, those of us who like cookies, cakes and ice cream, in order to reduce the tariffs and bring down the prices.
Maybe that is just the American baseline? Plenty of people enjoy cakes, cookies, doughnuts, brownies, etc that will be made with real sugar either at bakeries or at home. 60pounds/year is ~2.6oz/day (74g/day) which sounds pretty achievable given a once or twice a week snacking habit.
looks like a decade+ long decline trend abruptly stopped there and miraculously stayed flat for 20+ years