I think you're optimizing the wrong thing here. We don't need to be hyper efficient in terms of Sun's energy, as it's one of the most abundant sources of energy

I think you're optimizing the wrong thing here. We don't need to be hyper efficient in terms of Sun's energy, as it's one of the most abundant sources of energy available and will not run out any time soon. First one should optimize over land and resource use, as well as sustainability (CO2, fertilizer run-off etc.). Not to mention cost (including subsidies).