Well, technically it remains to be shown that we can't, risks of monocultures aside. We can keep moving the goal posts too if you want. Growing genetically engineered algae soylent green inside massive global greenhouses or perhaps even synthesizing sugars and proteins directly rather than going to the trouble of relying on photosynthesis. Technology keeps moving the goalposts of the possible.

Actually the opposite is true.
Since your proposal is so outside the realm how the observable natural world functions, it is up to YOU to provide examples of your claims.
Can you point to even region wide "massive" greenhouses? I think not.

Just because one observes the "goalposts" moving in the subset world of Man does not mean that same operative can be applied to Nature.

Your use of the term "technology" is also illustrative.
As though it has something to do with science.
The proposals you consistently post here are more in line with 1950's science fiction than modern scientific thought.
The only thing "technology" has moved has been Man's relation to the natural world and at his considerable peril as well.

Since your proposal is so outside the realm how the observable natural world functions, it is up to YOU to provide examples of your claims.

Well, its as observable as the total collapse of the human population. I think you're missing the point entirely. We dont know what the limits of support of technology are, only that it provides marvelous adaptive advantages to crisis. So much that people are actually pursuing the ridiculous idea of burning food as fuel as national policy (ethanol.)

I dont think we'll ever enter in some future where we have to do anything more drastic than irrigation and fertilizer production because benign demographic transition will make short work of population growth long before we have to enter into the silliness of some soylent green style dystopian race to feed trillions.

The point you think I'm missing is you DO believe we can monoculture our way out of our predicament. I maintain that the scientific, technological attitude that spawns such thinking is THE reason we are in our predicament in the first place.