It’s because caffeine is mote addictive than nicotine. You drink the chatged lemonade at Panera during your lunch break and think “wow! I felt great after my working kunch at Panera! I’m going back there more!” But that’s just because you are caffeinated up to your gills without realizing it. It’s the exact same as the story of a Chinese restaurant putting opium in the noodles to get people addicted to the shop.