This is the answer.

Considering life on this planet went through atleast 5 major extinction events and took 4 billion years to create creatures intelligent enough to leave the planet, it's likely that space faring civilizations are extremely rare. Now let's give a low range estimate that the first intelligent creatures arrived approximately 4 billion years after the big bang, that gives them at the very maximum, a 9 billion light year sphere of radio broadcast. Given that the observable universe is 93b light years accross, that first civilization would have only sent out radio waves in 10% of the universe, which means we could very easily be in a part of space that it hasn't reached yet.

This all falls apart if FTL is achieved, but I suspect if that's the case, then it won't really matter.