vaping delivers nicotine differently than smoking. iirc, the acidity of tobacco smoke allows the nicotine to be absorbed much more quickly. cigarettes also contain other (more dangerous) psychoactive compounds not found in vape liquid. from the chemical delivery perspective, the cigarette is preferable to the vape. the vape is fighting an uphill battle against the cigarette; it's winning now because it has fewer (noticeable/known) health effects and tastes better. if you start removing the flavor advantage, people switch back to cigarettes on the margin.