> Plants are grown on surfaces measured in tens of percents of country sizes.

That is cereal crop agriculture, which can't be done in vertical farms anyways.

Stuff like this is targeted at vegetables and herbs. There are still scale problems, but nothing like the kind associated with cereal crops.

The main issue as I understand it is that the sun is free outdoors, so it is hard to justify the cost of the equipment for indoor LED horticulture.

Talking out aloud here...could vertical farming help here? My theory is that we only use so much land because it needs access to the sun. If we use LED's and stack vertically, we can condense down the footprint.