There's a big problem though, I've written about it here https://www.ryanmercer.com/ryansthoughts/2014/11/30/this-jus...
Basically time + the vastness of space = an insanely low probability that any two intelligent civilizations would overlap within a detectible sphere, especially with our current level of technology.
If we assume 1,000,000,000,000,000,000,000,000 planets exist in 100 billion galaxies and that 1 in 100 of those host single cellular life, that 1 in 1000 of those host multi-cellular life, that 1 in 1000 of those have animal life, that 1 in 10 of those has sentient tool-building species you then have 10 trillion planets with tool-building species.
If we assume an even distribution that's 100 tool-building species per galaxy spread out over 12-13 billion years.
Oof.
Even if you make far more generous assumptions, and that 1 in 2 planets has single cellular life and that 1 in 2 of those have tool-building life. That gives you an average of 25,000 tool-building worlds per galaxy, something like a 1 in 20 million change any star in our galaxy has a tool-building civilization.
If you remove the first billion years of the galaxy you get 12.21-12.51 billion years.
Again if we assume an even distribution and assume 140,000 light-years in diameter for a galaxy, that gives you something like 1 tool building civilization per 600,000 square light-years spread out over 12 billion years.
:( :( :(
I would, however, expect at least one such civilization would develop within our detection range. As our range increases, both in distance and in breadth, chances should get increasingly better.
In the same way an ant might stumble across a human building or notice a human above the grass, you would think if life was so prevalent in our galaxy that there would be some sign of their technology.