The Fermi paradox concerns why we don't observe evidence of alien life, such as megastructures. If we were to build a Dyson swarm, the best source material may be Mercury (Armstrong and Sandberg 2013): not only is it close, with plenty of solar power for exponential disassembly, but its mineral composition is suitable. But could planets made of suitable minerals, with plenty of solar power, be rare enough to prevent most advanced civilizations building Dyson spheres, or other detectable megastructures?
It's a mundane solution to the Fermi paradox, but it's conceivable on my limited knowledge of exoplanets, if only because our planetary system is atypical. For example, where we have Mercury, many systems would have hot Jupiters instead (or possibly as well, if that's consistent with how most systems form). Can we begin to answer this with our current understanding of what's typical for exoplanets?