Vaping =/= smoking, it's not as simple as taking two numbers side by side and having a result. It's not rocket surgery but it is more complex than that.
A lot of nicotine in tobacco gets burnt up. Now, if you were to eat a couple smokes you'd get very very very sick, hastily. Not just from the taste (ugh) but because it's toxic and that's what the body does when it's poisoned.
Needless to say, PAD+ smokers usually start on 24-36mg juice and don't generally suffer from nicotine sickness, but they ARE getting an adequate amount to keep cravings at bay. So no, you don't have to vape half a litre to get a pack of smokes. I don't even think it's possible to vape that much in a 24 hour time span.
Oh, I also read that 100% nicotine is actually 1050mg, it's just easier to round down to 1000, those extra 50 are a drop in the bucket.
Oh Oh. I think cigarettes are more efficient at nicotine delivery. Ammonia is added to "freebase" increasing its absorption, plus the fine particulate do a great job at creating lots of itty bitty cuts in the lungs and esophagus, allowing it to move more freely directly into the blood stream. They're very specifically designed to give you the most nicotine as quickly as possible.