Discussions of the Fermi paradox get swamped with people's individual hypotheses. It's nice to see an article that tries to develop a whole different kind of answer. The known possibilities seem to be:
1. We're alone (or very nearly so) due to an early filter. i.e. it was vanishingly unlikely for life to develop as far as it has here.
2. We're alone (or very nearly so) due to a late filter. i.e. life develops in lots of places but, terrifyingly, it becomes overwhelmingly likely to wipe itself out rather than spread.
3. Life develops frequently but there's some sort of interstellar ecology that makes species stay hidden or be wiped out.
4. Life develops frequently but is overwhelmingly likely to develop some other interest (becoming inward-looking, or exploring other dimensions) rather than colonising all of space.
This article's suggestion that Earth may be in a backwater wouldn't be sufficient by itself, so it is coupled with the idea, derived from observations on human colonisation of Micronesia, that expansion happens in waves and life on Earth happens to be in between waves. The problem is, advanced technological civilisations expanding across the galaxy isn't the same thing as Polynesian explorers eventually being followed by Europeans. Why would the waves die away? This is a late filter with extra steps.
5. No Aladdin's lamp. There's no FLT, no wormholes, no solution to the huge distances. And/or interstellar space is so full of toxins or plasmas no lifeform can survive it. And/or all EM data transmissions are reduced/scrambled/swallowed/encrypted by the void. All the experiments are naturally locked in separate containers.
6. Klaatu barada nichto. We are indefinitely locked in solitary, incommunicado, for creating and using nuclear weapons. On ourselves. Immediately.
I find (6.) somewhat anthropocentric in that it assumes nuclear weapons are the nec plus ultra of destructive power. You might as well have said in 1917 that we were incommunicado for inventing chlorine gas, or shotguns (whose use the Germans did object to as a war crime!)
They aren't. We almost have the capability to do much worse ourselves already. If you want big-bang type weapons, you can modify an asteroid orbit to drop a K-T event on the planet. It's not very target-able, but if you want to try and wipe out civilization, it would be pretty effective.
6. is interesting because nuclear weapons are hardly the worst weapon possible. Even a relatively small mass accelerated to relativistic speeds would be more dangerous than a nuke, or even a very large mass at far lower speeds (asteroid). Similarly a genetically engineered biological weapon would probably be far more effective if total destruction is your goal.
Or 7 (is it now?), based on a thread above, organic civilizations become machine civilizations, which can colonize much more efficiently because long journey times don't bother them, and more stealthily because they can make do with comets and moons and such that won't support organic life.
1. We're alone (or very nearly so) due to an early filter. i.e. it was vanishingly unlikely for life to develop as far as it has here.
2. We're alone (or very nearly so) due to a late filter. i.e. life develops in lots of places but, terrifyingly, it becomes overwhelmingly likely to wipe itself out rather than spread.
3. Life develops frequently but there's some sort of interstellar ecology that makes species stay hidden or be wiped out.
4. Life develops frequently but is overwhelmingly likely to develop some other interest (becoming inward-looking, or exploring other dimensions) rather than colonising all of space.
This article's suggestion that Earth may be in a backwater wouldn't be sufficient by itself, so it is coupled with the idea, derived from observations on human colonisation of Micronesia, that expansion happens in waves and life on Earth happens to be in between waves. The problem is, advanced technological civilisations expanding across the galaxy isn't the same thing as Polynesian explorers eventually being followed by Europeans. Why would the waves die away? This is a late filter with extra steps.