Paul Davies (noted astronomer and popular science writer) published an article today in the NYT, of which I will essay an executive summary.
We really do not know anything about the probability of the origin of life, given accommodating environments, because we have a sample of only one, Earth, which tells us nothing about probability.
So, recent analyses that suggest that watery worlds somewhat like Earth may be relatively common in the Galaxy (and all other similarly situated galaxies, which may well number in the trillions in the wider universe), actually don't give us any information about whether life in the universe is common, rare, or even unique to Earth.
Of course, most scientists have a "hunch" that life is common, but the truth is we just don't know. The origin of life is an intractable problem; it has not yielded to experimental investigation and there is no well-worked out a priori theory that predicts from first principles that life must evolve from non-life. Again, we just do not know, however "sure" we may feel about it.
So, what then?
To me, this is a very strong argument for the extreme importance of searching for signs of life. There are very promising research projects being worked on and proposed to investigate the chemical signatures of life in the atmospheres of planets orbiting other stars. I would like to suggest that, after research into ameliorating and correcting the effects of climate change, including the development of renewable energy sources and sustainable methods of food production, etc., this is the most significant scientific question of our time.
Because, and this is a critical point, as soon as we have strong evidence of a biosphere anywhere other than Earth, it can then be accepted as a near certainty that life has originated in multiple locations in the universe; and if we find more than one; we can even come by some kind of estimate as to just how common it is.Why is this important? Well, it just is. If you don't have enough of a sense of wonder to see that, I can't convince you.