To quit smoking is to stay committed to it. But the question here is how active is a habitual smoker when it comes to quitting the habit. It takes a lot of courage for a person to get out of their bad habits because their body is already used to it. This is why you get a lot of feedback from other habitual smokers saying that it is impossible to quit.
It is not impossible to quit. It is just that people are too addicted that they already conclude it is impossible.