As mentioned in another comment, efficiency is not a bottleneck. You don’t have to rely on solar radiation toward Earth to increase entropy for fun and profit. There are other energy sources around. We are not using fission much, we are not spending nearly enough resources to figure out fusion, geothermal is all but untapped, there are countless other sources, as well, and that’s just on Earth.
As mentioned in another comment, efficiency is not a bottleneck. You don’t have to rely on solar radiation toward Earth to increase entropy for fun and profit. There are other energy sources around. We are not using fission much, we are not spending nearly enough resources to figure out fusion, geothermal is all but untapped, there are countless other sources, as well, and that’s just on Earth.