Another possibility is that intelligent life is relatively common, but highly technological civilizations are rare. How would human civilization have panned out if we had not been lucky enough to discover huge, easily accessible reserves of petrochemicals? We might have continued to enjoy a population and standard of living comparable to the 1700s, but not progressed to become the energy intensive civilization we are today. One could argue that would not necessarily be a bad thing in the long run.
It's also worth remembering that for 99.9% of our existence as a species, we lived on a much smaller energy budget. So maybe that's the norm, and planets where Saudi Arabia scale reserves of free energy are just sitting there for the taking are quite rare. Then, of those that do, what percentage successfully make the transition to become long-term spacefaring civilizations?
For a good read on the Fermi paradox, be sure to check out David Brin's The Great Silence.
It's also worth remembering that for 99.9% of our existence as a species, we lived on a much smaller energy budget. So maybe that's the norm, and planets where Saudi Arabia scale reserves of free energy are just sitting there for the taking are quite rare. Then, of those that do, what percentage successfully make the transition to become long-term spacefaring civilizations?
For a good read on the Fermi paradox, be sure to check out David Brin's The Great Silence.