But we didn't exactly choose this planet for our explorations randomly. We explored here because we lived here, and found there is life. Can't really extrapolate from that.

Just a thought. As you yourself say, we know only of one planet with life. However, looks like life only arise once on this planet. If life is so abundant in the Universe, why wouldn't it at least arise several times independently on the planet where the conditions are so great?

It would have to die off before it could arise again. Fortunately with a Hillary Clinton administration looming, we may get to see that scenario play out.