I hate to say it but we're still very much a fringe market, not worth their investment. Despite the rapidly increasing number of vapers, we're still only a fraction of a percentage of the number of smokers. We don't even match the number of habitual patch and gum users yet, and no major tobacco companies have done much more than dip their toes in the waters of alternate nicotine delivery systems, despite their having been around for decades now.
Ask youself when the last time you saw a vaper "in the wild"...one that you didn't introduce to vaping yourself. Odds are that unless you've been to a meet-up, you've never seen one. Now ask the same thing about smokers. Until our numbers increase by orders of magnitude, we don't pose an economic threat, and therefore we are not of the slightest interest to major tobacco producers.
We don't fit their business models...not at all. to be honest, there are FAR more recreational ......... users than there are vapers...THEY do fit the tobacco companies business model, far more closely, and you don't see Philip Morse lobbying for legalizing pot.
It's not likely that you're going to see a major North American company manufacturing juice, or e-cigs in most of our lifetimes. It's pretty simple econoomics...they will go where the money is, and it ISN"T in vaping...yet.