I think this makes a lot of sense but surely it's the nicotine in smoking that gets people addicted? If we're still getting the nicotine, we would still crave the caffeine?
How much nicotine we're getting compared to cigarettes is a tricky one too. I heard we absorb less nicotine than by smoking. If I smoked 1mg rollups and 20 a day of them, and now use 1.5ml of 11mg juice, surely I'd be on less?
Its a really weird one isn't it?
I think a large part of it for me is habit. It was always 'a cup of tea and a ...' (a colloquial British term for a cigarette and in no means intended as a derogatory term against any demographic!). My best friend and I would drink as many cups of tea as cigarettes we would smoke whilst visiting one another and there were times when it could be literally continuous. The act of making tea was as much a part of having a cigarette as smoking it.
Boy, I miss my caffeine! I feel like such a sell-out! If it wasn't bad enough that I'm weening myself off nicotine, I'm weening myself off caffeine! I'm gonna need a new vice...x
There's a lot more in cigarettes than just nicotine, there are various alkaloids that act like antidepressants, for instance. Consuming just nicotine isn't the same as consuming all the various chemicals in cigarettes, which is partly why smoking is so hard to quit, because replacements don't always replace everything that you miss from smoking. This is the reason why some antidepressants are used off-label to help quit smoking, like wellbutrin, which also has stimulant effects in higher doses btw, and it acts a little differently than most antidepressants.
Some people could very well simply be addicted to nicotine, where as other people may become smokers because it helps them regulate their emotional state due to the antidepressant qualities of some alkaloids in tobacco. Think of someone who takes actual antidepressant pills, they aren't supposed to just stop taking them, but that's exactly what smokers do when they quit smoking, which can contribute to their distemper while quitting, and explain why regular nicotine replacement therapy doesn't work, because it's not the nicotine they really needed.
There are a lot of variables involved obviously so it's hard to say what's going on with a specific person.
On the subject of how much nicotine is being absorbed, that also varies by quite a bit. Some vapers might only be getting trace amounts of nicotine actually absorbed into their bloodstream while others may be getting way more than when they smoked.
Personally, I'm pretty sure I'm getting way more nicotine now. I chain vape almost all day, and at least a few times a week I generally get a slight headache or feel sick because of a slight nicotine OD, as I vape past the point of simply being satisfied, because the juice tastes so good
I've had high blood pressure for years which is bad considering I'm not really at the age where high blood pressure is normal, so I test mine at home with a meter somewhat frequently. After switching to vaping my blood pressure on average has gone up, which I assume is due to me getting far more nicotine than I used to with cigarettes. The few times I've slipped up and smoked real ciggs I would generally smoke 2-3 in a row because I didn't get the nic fix I was expecting, something I never did when I was a smoker, one cig and I was done for at the very least 30min.
So it really all depends on a lot of factors, so I was just bringing it up as a possibility for the OP. It's up to them to figure out if it matches their own personal experience.