Addiction doesn't really work like that. Surely water is better for you, and also "feels" better after a good work out. But put coke in front of people who are semi-addicted to it, they will choose coke.

BTW, almost all water served at restaurants in China is lemon flavored. The best halfway point I've seen is flavored soda water. Fizzy, slightly flavored, gives you some of the feeling of pop without the sugar. Still, put coke in the same fridge, and it requires some willpower to take the flavored soda water.