I think it stems largely from the decades-long anti-tobacco crusade spawned by government institutions as well as entities like the World Health Organization
After a failed attempt in the 1990s and early 2000s, backed by an enormous advertising push to convince the smoking public that switching to smokeless tobacco or the newly introduced product, snus, would be a better alternative for enjoying tobacco (based on what was called the Swedish experience, which has never been replicated elsewhere), harm reduction proponents became intrigued with the even newer electronically heated nicotine vapor products that emerged from China
R.GlajchJ
Over the last 100 years, the industry has successfully adopted and implemented the Integrated Tobacco Production System with small scale farmers in growing tobacco
The average cigarette contains upward of 600 different ingredients on top of over 7,000 chemicals produced by cigarette smoke
Gunduz I, Kondylis A, Jaccard G, Renaud J, Hofer R, Ruffieux L, Gadani F (2016) Tobacco-specific N-nitrosamines NNN and NNK levels in cigarette brands between 2000 and 2014