It's crazy to say that our not having found life elsewhere yet implies that it's especially fragile considering that we've barely had a chance to check anywhere. Even Mars, the planet other than Earth that we've been able to spend the most time exploring remotely, may still harbor life. We literally have samples sitting there on its surface that might prove there was once or is currently life there. There are also moons in our own solar system that we suspect might have life, but we haven't really had a chance to properly check. Forget about all the potentially Earth-like planets we find elsewhere.

Drawing any conclusions about how common life is from our extremely limited current ability to look for it is more than a little absurd.