|Is one of these things really not like the other?|
But there is a reason why nicotine users seem to need a "fix" more often than caffeine users. Consider the fact that a Starbucks latte in the morning and a 5-hour Energy drink after lunch equals about 350 milligrams (mg) of caffeine a day. The half-life of caffeine in the human body is 6 hours (meaning that after 6 hours, only half of the caffeine consumed has left the system), so the effects of caffeine last a fairly long time. Just two strongly caffeinated drinks can last a caffeine junkie all day long!
Now consider that smokers consume about 200 mg of nicotine a day, but scientists estimate that only about 10% of that (20 mg) is actually delivered/absorbed by the body. (Personally, I use my e-cigarette all day long, but still use only about 3 ml of 12 mg strength liquid which, using the same 10% delivery/absorption rate, would be only 3.6 mg absorbed per day.) The half-life of nicotine is only about 2 hours, so unlike caffeine users, nicotine users have to use it far more frequently to keep getting its benefits. That makes it look like they "can't live without it," but caffeine users just are fortunate that the effects of their "drug of choice" last longer!
If you consider these facts, smoke-free nicotine users aren't anymore "addicts" than caffeine users. The only differentiating factor is how the nicotine is consumed. When the nicotine is consumed by smoking, that can have serious health consequences for the smoker and negatively impact their life. But it is the inhalation of smoke that is creating the problem, not the nicotine dependency itself.
So why aren't people who depend on caffeine to get through their day considered "addicts?" Mainly because using it generally doesn't have a negative impact on the user's health and quality of life and people feel they derive a benefit from its effects.
How is that any different than a smoke-free nicotine dependency? If you know the facts, you know it isn't different at all.