tosei (npub19af…pq9e)
Reading more of Chefurka:
http://www.paulchefurka.ca/Fermi.html
He did it again, reached almost precisely the same conclusion that I did!
The way I've been phrasing it is that aliens squandered their fossil fuels before they'd developed comparable renewable sources and established an off-world presence, and THEN got trapped on their little rock because they had no more massive stored energy to finish the work of getting to the stars or at least other planets. Definitely no Dyson Sphere, not even a Halo Ring....
I was for a long time worried that would be US. Seeing how quickly we can now migrate to (sorta) renewable sources, however, I wonder if we might still escape that fate. Although... we'll likely need fusion to fuel a mass migration to other planets or stars.