The 50s analogy is only to point out how we like to extrapolate contemporary technical understanding into the future. The envisioned dyson spheres I've seen loo

The 50s analogy is only to point out how we like to extrapolate contemporary technical understanding into the future. The envisioned dyson spheres I've seen look like our current understanding and use of photovoltaics extrapolated in the same way. I don't disagree that the core idea of harnessing the suns energy seems likely. As the parent poster said, it's just the absolute confidence that people seem to have on the subject that's a bit curious. Maybe breakthroughs in energy generation will make it not worth the effort? Maybe becoming interstellar makes it obsolete since the energy requirements for a given civilization are spread thinner? Maybe there are other ways to harness the solar energy that would not show the same signs as we predict? Maybe civilizations trend to energy efficiency instead of just increased usage? Maybe not.