This filter applies even before they invent technology. Brains use lots of energy and development time. This is typically selected against. Therefore most organisms only evolve the minimum amount of intelligence they need. And human level intelligence is never an advantage in most environments.
So you need some really weird set of conditions to create an environment that selects for high intelligence, and doesn’t select too strongly against energy efficiency or development time. I don’t know what these conditions are, but they only occurred once on Earth, over hundreds of millions of years. This suggests these conditions occur very rarely, and we might just be very lucky.
This filter applies even before they invent technology. Brains use lots of energy and development time. This is typically selected against. Therefore most organisms only evolve the minimum amount of intelligence they need. And human level intelligence is never an advantage in most environments.
So you need some really weird set of conditions to create an environment that selects for high intelligence, and doesn’t select too strongly against energy efficiency or development time. I don’t know what these conditions are, but they only occurred once on Earth, over hundreds of millions of years. This suggests these conditions occur very rarely, and we might just be very lucky.