1 such farm on 1 acre of land (the size of a football field) and 44 stories high can produce enough food to feed 613 000 people (10 different vegetables per person daily).
The on going problem with this silly idea is that unless you make your 44 story building extremely narrow, and
capable of rotating to continuously face the sun, only the plant life near the building's windows will grow. And only on the side facing the direct sunlight.
The plants of the top floor would however grow quite well.
Of course you could grow mushrooms in the vast majority of the building's interior, they don't require direct sun light.
I like mushrooms.
Ever heard of Omega gardens that grow food hydroponically in hollow cylinders which rotate around their own axis containing a light source in the middle? This kind of system grows food up to 5x faster (because it forces the crops to fight against gravity)... independently from the outside light source (which is provided by the light in the middle) - we can also grow fish and have a completely closed system for nutrient rich water (of which, only 25% [of what is presently used in agriculture] this kind of system would require).
1 Omega system can produce up to 80 different plants (which contain a high number of nutrients compared to stationary crops).
Oh and this would eliminate usage of pesticides, chemicals and GMO.
Really they weren't. Certainly not on the scale you're suggesting.
Actually, the concept of hydroponic farming dates all the way back to the 1940-ies (as do atmospheric water generators).
Robotic arms were invented in 1956 (similar time frame is there for invention of solar panels)... and I'm pretty sure that the concept of vertical farming (in high rise buildings) existed since the mid 20th century at least (there is also evidence that a tower hydroponicum existed in Armenia before 1951).
So... I would argue it was possible for decades now on the scale I'm suggesting (in the end however, it would be done TODAY - and we can further refine/enhance the process/technology if we used state of the art methods of production and superior synthetic materials - as opposed to currently used methods of production and inefficient materials).