The pharmaceutical industry doesn't care about smoking cessation drugs except as an indicator to how their real smoking-related markets will react.
Yes, NRTs and psychoactive drugs for smoking cessation are a ~$5 billion annual global market, but this is chump change compared to the main channels: (1) sick smoker treatment drugs and (2) the boost to general drug sales caused by smokers. Smoking creates at least 10% of pharma's gross income and it could even be as high as 15% or 20%.
1. The sick smoker drugs are immensely profitable as a near-monopoly situation exists: chemotherapy drugs, COPD drugs, cardiac drugs, vascular drugs etc. All these will take a 60% hit eventually although there is a long timelag in this market.
2. There is an enormous boost to general drug sales caused by smokers: diabetes, cholesterol, bronchitis and blood pressure drugs are examples. This is because a smoker is >40% more likely to be diabetic, and the same applies to many other conditions that drugs can be sold to treat. These conditions often can't be cured while continuing to smoke so the customers are permanent. Smokers will always need inhalers, diabetes meds etc. This market reacts faster than for example the chemotherapy drugs market.
In addition there are other income channels such as OTC meds that are boosted by smoking.
These huge income channels (possibly worth $200bn a year), plus the close integration of pharma with the legislative and regulatory systems, are the reasons why pharma is the strongest and most effective opponent of THR products such as ecigs. It's why they fund a range of front groups to promote their agenda: ban/restrict ecigs, in order to protect their income by protecting smoking. It's why cancer 'health' orgs are in the strange position of protecting and promoting cancer by helping to block ecigs - these groups are controlled by pharma. They pay the CEO $1m a year to keep the faith, so don't expect any honest 'cancer health' orgs anytime soon. They all need to protect smoking, it's the gravy train that pays all their mortgages.
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And I suppose it's worth adding that the reason why this is allowed is because anything connected to smoking is essentially a free-fire zone: smokers are considered already dead or addicts without rights. Industries can profit from smokers or restrict smokers in ways that would be impossible in other market areas. Smokers are basically considered to be an already-dead tax and profit source. Smokers have no rights, and ex-smokers have no rights either.