The Universe is really big

We're not as interested, nor have the ability to see and learn what's out there, currently. Unless you're suggesting we simply dump all of our labor and resources into discovering and learning what's out there. Making the whole world collaborate in a group effort to reach out to the stars. In which case, that's no better than what religions focus on. "Your current life is only a precursor to what's after your life! Adjust your life to follow this and you'll find salvation! It's not proven or anything, and you're taking a big risk, but if you believe in it without a doubt then you've nothing to worry about!"

Essentially throwing away everything we have here to go have fun exploring isn't something most people would want to do. Most humans are pretty selfish deep down inside, one way or another. We wouldn't want to focus on what's going on out there if has nothing to do with us.

I hardly see what your point is? No where did anyone say anything about afterlives or salvation or any of that. If for nothing else those selfish people should see the value that can be gained from a trillion untapped worlds.

because humans are incapable of knowing what the rest of the universe is, as its ever expanding.
and i remember seeing that image many times before...

So? that's no reason not to start trying. If anything, it's all the more reason to start now, because the longer we wait the harder it will be.