Much of that "empty desert land" has vibrant eco-systems. There is the power loss in transmission and the materials use of long transmission lines. Deserts are high heat lending less efficiency but worse is sandstorms grinding at the panels and the up lift is very strong, so substantial structures would have to be added to the natural landscape. More money and waste, and it still would not be nearly enough to replace the coal plants. Gen IV would, but we only have 9 years to reduce emissions from all human sources 90%.
Can we go to that kind of steady state environmental economy, needed also?
Logistics alone says humans will do too little too late, but psychology has the same result.
How do you get 7.2 billion people to do the right things? It is equivalent to herding cats.
Time is the thing that is running out very fast, as overpopulation and emissions continue to grow.