No, it's a political one. A lot of people have spend a lot of work (and lobbyists probably paid a lot of money) to bring us to this point.

Some years ago in Germany there were a lot of people starting with vapes instead of cigarettes. Doing their own coils, mixing their own flavors... so they first restricted premixed liquids containing nicotin. Then they restricted the sizes in which nicoltin shots could be sold. And then (given that a lot of people actually had reduced the nicotin ratio anyway) they threw all "but it's for health reasons"-pretense overboard and are now taxing basic glycerine and propylene glycol bases used for vaping as if they contained nicotin as they could be mixed with some. Meaning that I would have to pay more for 10ml now than for a liter bottle before. And of course buying those freely available liquids used for a lot of other things and using then in my e-cigarette is now tax fraud (and massive one as a 10€ 1 liter bottle now costs about 600€+... all taxes).

This has nothing to do with economic reason. They intentionally basically banned the economic option, so companies (affiliated with tabacco comapnies) producing that electronic waste could get rid of the competition.