The Fermi Paradox: The Stay at Home Hypothesis II (a.k.a., The Economic Impasse Hypothesis)

The second SAHH suggests that the technological factors that restrict interstellar travel and communication, (e.g., the speed of light, interstellar dust, and so forth) simply make in uneconomical for any species to invest in such activities on any but the smallest scale (e.g., probes to local solar systems and broadcasts only to the very nearest set of stars). As such, intelligent life may be common in our galaxy, but travel and communication would be so restricted that we should never expect to encounter any evidence of it.

Critics of the second SAHH argue that this hypothesis presumes that current limitations on technology can reliably be imagined to apply to future technologies. Proponents of the second SAHH counter that neither can one simply presume that a sufficiently advanced technology will be able to circumvent the known laws of physics.

Critics also complain that applying economic principles to extraterrestrial intelligences is patently anthropomorphic. Supporters of the second SAHH reply that economics isn't merely a human convention, but a universal description of how limitations on resources have an impact on actions. They point out, for instance, that many of the principles of economics apply directly to the evolution of biological systems.