Have to question your statement "If we have yet to face the great filter, our future seems bleak." Doesn't this future "great filter" logically include anything that can hinder us from colonising the galaxy as fast as the laws of physics permit spacecraft to travel? And why would the "great filter" be just one thing? Couldn't it be a series of things, a series of challenges? You've mentioned two that we face right now, climate change and bombs. Maybe they are only the first in a series of hurdles which we (or any technological civilisation) will have to get over before we (or they or it) can get anywhere near colonising the galaxy. The hurdles may be high enough, and numerous enough, that they've prevented civilisations like ours from colonising the galaxy so far; but that wouldn't necessarily mean that no-one will ever get over them. Is it "bleak" to think that there' a chance the galaxy will never get conquered by a technological civilisation? Is it "bleak" to think that even if the galaxy does eventually get colonised by a technological civilisation, there's a chance it will be someone else's civilisation? Why do you see rapid earthling expansion through an otherwise lifeless galaxy as the only scenario which isn't "bleak"?