This a bit like AI. It's 2018. Where are your vertical farms? You want to talk efficiency, soil on the ground will be more efficient than soil in the air for at least the next 50 to 100 years.

Eventually we'll even live in starships and colonize distant planets if we don't kill ourselves first, but I'm going to go out on a limb and say that will not be our defacto mode of living in my life time, and the same goes for vertical farms.