life is a thermodynamic process, it exists at that gradient between "hot" and "cold". life takes Energy, organizes itself at the cost of disorganizing the universe slightly more, and expends waste heat into the cold of the universe. the "habitable zone" is where this process works best, the chemistry works best, it is where it is most likely to occur. it is not "random" as you put it, but rather on a bell curve of probability. , too hot, low chance.. too cold.. low chance..

now life may very well exist on titan, and when more probes are sent, they will either confirm it or deny it. however the probability of life existing there is not so great, simply because it's too cold, and the chemistry and thermodynamics don't support it