It is necessary to note, however, that the great filter does not necessarily occur when a civilization achieves some arbitrary technological level.
In fact, it could be at the point of single cell --> multi-cellular organisms or at the point of sexual dimorphism or developing general intelligence and ability to use tools, etc.
I guess it's also possible there are multiple Great Filters...
That's a good point, and you're right of course. In fact I take some hopeful comfort in the notion that while the leap from organic molecules to single-cells might not have been too big, there are some indication that going to multicellular life was a leap that took quite some time. We still have reasons to hope, but we're doing almost all that we can to extinguish that hope.
In fact, it could be at the point of single cell --> multi-cellular organisms or at the point of sexual dimorphism or developing general intelligence and ability to use tools, etc.
I guess it's also possible there are multiple Great Filters...