It is a bit weird, isn't it? It makes more sense when you think it through. Kind of a classic modern American capitalism story.
Vaping started out as kind of a hobbyist/DIY thing, long long before Big Tobacco came along. Ruyan--the original Chinese manufacturer of ecig hardware--started shipping internationally in 2005 or so. Gradually it developed into a cottage industry with mom&pop type operations mixing their own juices to sell and selling hardware on the side--ordering from china sucks for an individual order, and a lot of people were suspicious of the Chinese liquid and wanted American-made. So we got all kinds of small businesses like Mister-E-Liquid, MadVapes, Mountain Oak Vapor, etc growing and starting to cater to mail-order customers in the states, as well as making better and improved hardware. Eventually Big Tobacco noticed this growth sector. The super-big players--Lorrilard & Phillip Morris-wanting a larger slice of the nicotine marketshare now that their cigarette profits were declining, bought up some of the less reputable, heavily advertised, low quality, high-margin e-cigarette companies (Blu & Njoy -- you see these crappy proprietary 510-style units in gas stations). They haven't done too well despite advertising campaigns, since the hardware is terrible and the juice is often even worse.
Now we're in a position where no one wants to buy Big Tobbaco's hardware and juice. People want to be able to buy from reputable smaller suppliers and manufacturers that provide higher-quality hardware (variable voltage mods, high-capacity batteries, long-life manual switches, rebuildable atomizers and tanks) and good-tasting juice. Big Tobacco doesn't want to get involved in these things because they aren't Big Profit. So Big Tobacco did what Big Business does best -- lobby and use political connections and influence to edge out and eliminate their competition.