i worked in marketing in this field. Theres way more behind this than one would ever imagine.
1. there's a "main street" in every shop. All producers wanna have their products placed there. It generates the most money. Lots of people just walk the main street. Only top-seller can be found there.
2. eye catching places are very important. eye level is the most expensive.
3. as a shop owner you have two possibilities to place a top-seller. i) on the "main street" ii) somewhere where hardly noone would walk to ... just to give that place some more chance
4. Fruit and vegetables are mostly placed at a very good location in the store. Not because the shop owner make tons of cash with that, but they have to sell all of it it everyday ... they cant used it the next day anymore
5. Music gives a better shopping feeling
6. Kids stuff is mostly placed near the exit. Children dont really like to go shopping with their parents ... so the longer a family is in the store, the more stress. You know what happens when they finally reach the toys corner
7. .... and so on ...