[sandspar]

I don't understand why people fixate on Dyson spheres. Why would a Kardashev type 2 civilization rely on something that a type 0.7 civilization could come up with? Surely in the intervening 1.3 they could come up with something we can't. Dyson spheres are a type 0.7 imagination exercise. A type 2 civilization wouldn't just extend our technology - it would transcend it. Maybe they use dark energy, maybe they gather energy from simulations. We can't understand.

[kulahan]

There are billions of engines sitting around the universe; might as well just use those.

The more advanced versions tend to simply use more radiative heat. they might arrange stellar nurseries, modify stars to be more efficient, or use black holes for engines, but even then you’re still just feeding them stars anyways.