That's Frank Drake's answer to the Fermi Paradox. He doesn't think it is a paradox, because he thinks it's just a matter of time before SETI makes a detection. It's just that the search needs to be thorough enough since the aliens stick to their solar systems.

Jill Tartar has talked about how we would need to think about investing in a powerful radio beacon for 60,000 years if we wanted other aliens to know about us. That gives one an ideal of the scale of time and distance SETI is dealing with, assuming their assumptions are more realistic than Fermi's was.

Or we're in a simulation, and everything we perceive as "out there in the expanse of space" is just fake data like a background on a website...from a processing standpoint it'd be much easier to feed/render certain views only under observation, otherwise just nothing exists there...it's save resources for a simulation from a computing standpoint...

Like in a video game where new areas are rendered as you discover them....