The Great Filter provides no explanation here. There are four options: early filter, late filter, multiple (early and late) filters, and no filters. In the first three cases the existence of early filters is explanation for an empty sky. (We are getting very close to the capability to build von Neuman probes though, so I'm not sure an o sky is evidence for a late filter.) In the case of no filter however, we can expect that any intelligence would start expanding into the universe at near the speed of light. So the fact that our light cone doesn't contain other intelligences, so far as we can see, is also consistent with no filter. An observation which is evidence for a proposition being both true and false doesn't provide any useful evidence.