“The universe is so vast that it may be teeming with life...”
It might also be teeming with giant marshmallow men, but it’s not. Modern man just hangs all of his hopes on one extraordinarily unlikely supposition because he despises admitting the consequences of that supposition not being true.
Most people do not really understand how vast the universe is. They estimate there are hundred of billions of galaxies. The nearest real galaxy is Andromeda which is 2.5 million light years away.
I would claim that Man will never explore Andromeda or the other hundreds of billions of galaxies. The distances are too great.
The Milky Way is hundreds of light years across. I doubt we ever explore more than a subset of our own galaxy.