I’m not saying the math checks out, but the argument is that you get full sun with no atmospheric losses 24/7, so you produce way more energy per panel, and you don’t need batteries, because the power production is consistent and predictable.
Unless someone figures out how to break the laws of thermodynamics there's never going to be a cost effective DC in space.
Edit: https://en.wikipedia.org/wiki/Planetary_equilibrium_temperat... A blackbody sphere near Earth's orbit balances out to almost exactly 0C. A sphere has about 4x as much radiating surface as capturing surface. A flat surface facing the sun that would have 2x, front and back.