I agree that life is very unlikely on any given earth-like planet. And most life out there is probably of the unicellular sort.
I also don't think its guaranteed that humanity will last beyond the point we can 3D print an antimatter supersoaker.
I am just saying that out of 50 sextillion chances, I bet enough planets evolved human level intelligence that at least one made it to the singularity. And given that most rolls of the dice happened billions of years ago, whatever the singularity turns into exists already, and has for billions of years.
I don't think this is optimistic in the slightest, I think its a very sober reading of the probabilities. I would actually say that thinking we're unique is the optimistic point of view.
But I think that what I'm saying feels optimistic because its contrarian, and its contrarian because our intuitions just aren't calibrated to reason through this sort of thing. A lot of it is because of our fiction. We imagine green space men because that's what actors dressed up in suits can portray. We imagine aliens like ourselves, don't find that, and conclude there aren't any of any sort. We imagine other civilizations out there to be contemporaneous with ourselves and on the same timeline because that's all we've ever seen. And we can't grapple with numbers like 50 sextillion because we're evolved to count bananas. But if you think about the odds we're the only intelligent life that evolved and just reason through it using numbers, how can you think we're alone? There are only 100ish atomic elements that matter. They're all pretty common. Our star is very average. The Earth is a pretty pedestrian rocky planet. The Milky Way is pretty average. Life emerged relatively quickly after the planet cooled (on an astronomical imescale). The fact that we look out into space and don't see anything means diddly squat because we can only observe 5 earth-like planets/moons out of 50 sextillion. But we feel alone and unique because we're evolved to assume that all we see is all there is.