"Can someone explain how the business model for indoor farming is supposed to work?" This depends entirely upon a bunch of various factors, but the major draws

"Can someone explain how the business model for indoor farming is supposed to work?" This depends entirely upon a bunch of various factors, but the major draws are that you can control the environment, and with specialized hydroponics techniques you can drastically reduce the usage of fertilizers and water to obtain an equal-quality crop. You can also drastically reduce the footprint required - in certain hydroponics systems, what would normally take 1 full acre of land (say, alfalfa) could be done in 1/8 of an acre. Depending on the crop, you can even get away without using light at all (most grass crops work with this) reaping even more savings on energy usage. Many of these farms are failing because they've got a bad mix of factors that they did not thoroughly think through before implementing. All of the farms I've set up in Australia, UK, and the Middle East are still working just fine, a decade later.