I don't know the numbers, it is indeed true that many of the tobacco companies are working on stuff, but they're years behind the curve. Also, I'm fairly certain that Phillip Morris was SURE the USA would allow their "heat not burn" product to gain a huge market share. They were roundly dismissed, and they spent SO MUCH in developing that thing. I think the businesses that were really vape only from the start are light years ahead most gas station cigalikes. I think there is a market share, but I don't believe that overall, tobacco companies are "ahead" in the vape market.
I kind of get the sense that either the FDA wants to reign in BOTH vaping and smoking, in different ways. If they go the way of the closed, tobacco flavored pod, then tobacco companies may have a chance... In the USA at least, of getting a reasonable market share, but ATM (and the Juul got popular, I think, prior to being partially purchased by big tobacco, IIRC).
So, I'm not entirely certain "how much" market share overall, cigarette vape products own, worldwide. It would be interesting TO know, but I'm not sure big tobacco is currently ahead.
I think if anything, they are cursing themselves for not going to Heat not Burn in the 70s. They considered it, and felt there would be too much "pushback." If they had gone ahead, vaping AND smoking would not be coexisting the way they are now, IMO.
Anna