Again, our proposal isn’t that we should cover all of this land in solar panels, or that it could easily power the world on its own. We don’t account for the fact that we’d need energy storage and other options to make sure that power is available where and when it’s needed (not just when the sun is shining).
This is a thought experiment more than a plan.
You'd be surprised how many people don't take the time to read a long article like that but will have a quick glance at the comments.