And actually, that is, in my view, the most important question. Cause and effect. There has to be a cause in the first place.
As I mentioned recently, if you take a fairly arbitrary distance from our solar system of say 25 light years, there are about 100 stars.
While that may sound a lot, in reality, it is not, given there are about 200 billion stars in our galaxy. And it is 100 thousand light years across
So the likelihood of two stars within such a short distance having species capable of interstellar travel has to be minute at best.