You have to account for the fact that, even if a civilization were to broadcast some sort of signal, it would take many millennia or eons for any signals to reach us. And even then, we would have to be advanced enough to be able to receive and interpret those signals at the same time they reach Earth.

There could very well be countless advanced civilizations whose signals just haven’t reached us yet, just as there may have been countless ones whose signals couldn’t be received or understood when they reached us, and they’ve died out or otherwise stopped transmitting before we could.

Keep in mind that the first radio broadcast on Earth was only 127 years ago. That means the farthest anyone could possibly detect any radio signal from earth is a mere 127 light years away.