it's about perception. you could apply the "junk Apps" to ios and android easily. but it doesn't stick because the general public's perception is there's choice. i used to run a small video shop in spain and we had sweets and bars etc. not lots but enough. the owner didn't want to buy much, just 4 different types of bars and some drinks because they sold quicker then the other stuff. i bought them instead because people want choice, they may not want the other stuff but they want the option of saying no to it. if you give people choice they will feel more in control and more likely to return because of the perception of choice.