I liked that Ringworld addresses this. What Dyson Sphere's excel at is hiding their location* and capturing 100% of a stars output. At those sizes, a civiliza

I liked that Ringworld addresses this. What Dyson Sphere's excel at is hiding their location* and capturing 100% of a stars output. At those sizes, a civilization MUST have already conquered the energy problem. It'd be impossible to construct without "free energy", because you need to convert that energy into matter to make/engineer enough material to create a sphere the size of the Goldilocks zone. And as you said, you'd lose atmosphere & gravity* would be wonky. But to address the fine article, the equation was a thought experiment. We now have hard data on the number of stars that we've looked at that have planets. And of those we have a hard number that have planets in the habitable zone. The Drake Equation presumes that you guess TINY numbers for those values. Well using known numbers and extrapolating the number of possible worlds with intelligent life jumps from staggering large, to incomprehensible. As humans, we can barely communicate with others of our own species. Let's frame the problem another way. Put two Americans in a room. One is deaf, the other is blind. How long does it take for them to agree on what to eat for dinner? Context depends on language. We may have been bombarded by intelligent alien life for centuries; we just don't know that somebody is talking. *Everybody forgets about gravity.