I think they'll be banned the same way clove cigarettes are banned, but easier to obtain (not that buying them from Indonesia online is any harder than buying anything else online).
If you really break it down, what are they going to object to on the hardware, other than the atomizer? Batteries? Plastic cylinders? Good luck with that. Even the atomizer... okay, instead of a smoking device, we now own ridiculously inefficient incense burners.
And liquid? PG and VG are impossible to regulate without annoying countless industries, and then there's the nicotine... very dicey ground, to say the least. Nevermind annoying the tobacco lobby, you've also got legitimate uses for nicotine that have nothing to do with human consumption. How're you going to regulate them all? And if you do, who's to stop me from producing nicotine liquid "for pesticide use only"?
Just about every head shop, adult store, and gas station (geez, I sound like a sleazebag!) sells fake-pot "incense" and poppers labeled as "VCR Head Cleaner" or "Leather Cleaner". There's nothing stopping them from selling Twinkie's Nic-a Nic-a Roach Liq (other than the possible trademark violation) with "NOT FOR HUMAN CONSUMPTION" in big red letters next to a rainbow of 0-nic flavored PG and VG "for external use only".
Now... if someone credible could prove that they're safe and legitimate smoking cessation / replacement aids...
I don't buy too much in to "RAWR BIG PHARMA!" conspiracy theories, but consider national healthcare for a moment.
For national healthcare or against it, I can tell you having paid for it out of pocket, Chantix is fairly expensive. As taxpayers, smokers or not, are we collectively okay with paying $150 per month per person for Chantix, or putting the FDA blessing on something safe, inexpensive, and not under the realm of prescriptions instead?