On the next page there:
"The amount of sunlight reaching a square foot of the earth's surface is relatively small, so a large surface area is necessary to absorb or collect a useful amount of energy."
https://www.eia.gov/energyexplained/solar/
And that's the problem. The square footage required to produce a useful amount is too great. Like I said, it can help but will never be a major source of energy for us. Slight efficiencies can happen, but that reality will never change.