This is a good question, and one that begs us to think of the possibility that if so much of the universe looks so similar, with familiar stars etc, then it seems unlikely that if the conditions for life emerged in one place, that they would not have emerged on countless millions of other places. We know that on Earth, life emerged under absolutely terrible conditions compared to what we now enjoy. At least at the level of bacteria, I see the universe as an enormous laboratory for synthesizing life. Whether all of this potential results in organisms that can think and build computers is not obvious to me at all. During the 3.8 billion years life has existed on the Earth, this ability only emerged in the last 50 years! So at least in OUT case, we needed 1) A chance impact that eliminated the dinosaurs, and 2) a long time to get here. Some environments may favor neither of these.
The question isn't why there are so many stars if life is an accident, because life is not an accident at all. It is just another process in nature like gravity and chemistry. As the universe cools, we end up with more and more complexity. Life seems to be one of these features.