I always go back to people like Drake and Shostak. They seem pretty convinced that "they" are out there, but the problem is that there’s no known way to communicate with them due to distance and time. If there’s a way to solve this problem, please let me know. Sagan and others seemed to think that if we could communicate (a very big if), then we could exchange our knowledge, but how exactly could you do that? The problems appear insurmountable.
I think we'd better hope that we're alone. If creatures like us are common then that's bad new for us, because "life that behaves like humans and exists for millions of years" and "a galaxy that hasn't been completely filled long before now" are mutually-exclusive states. If we have any chance at all of conquering the stars we'll be doing it alone.
Sure, plenty. They just mostly require us to change over time. Maybe sapient species mature and don't feel the need to ever expand, for millions of years. Maybe interstellar travel is so hard nobody ever does it nor do they make machines that do. What worries me, though, is it doesn't seem that impossible. It seems like if humans exist long enough one of us is going to make and launch a Von Neumann probe that eats the entire galaxy. The fact no alien species has makes me think we're far and away more likely to go extinct long before attaining that capability.
I remember a line from a sci-fi novel: "We only consider a species mature when you could put the power to destroy the world into the hands of every single individual with complete confidence that none of them will ever use it." I think we're, eventually, doomed.
I’m with you. But is it reasonable to assume that we can understand each other and share knowledge between the stars? From what I understand, it’s extremely unlikely. After all, we can barely communicate with species other than our own.
