Earlier quoted context omitted.
And because it's often the only option. Here's a question for you, which one happened first? A) someone packaged a good in plastic or B) someone bought a good packaged in plastic?
It's the only option because it's the best option. Without plastic what would you package things with? Everything is shit by comparison.
Going back will mean going to the market, getting fresh vegetables and potatoes and shit, and put them in either paper bags or reused burlap sacks. I think an individual's biggest contribution would already be changing their food habits; stuff like keto, primal diets, vegetarianism / veganism are a step in the good direction. Assuming you cook your own food, instead of idk, grabbing a McD's salad (in a plastic container) or pre-packaged vegetables (plastic bags).