Entanglement allows instantaneous communications without propagation, thus the primary signals we look for are not used.

All life has this ability (see snail telegraph) it simply isn’t as useful or efficient for organisms as one imagines (we aren’t computers however we are a technology.)

Further, consumerism and consumer-topia is not as popular. Most life in the universe stays at a feudal level even when the ruling elite discover and adopt technological advancement.

From the stories I’m getting (I know I know), civilizations apparently rise and fall without ever discovering radio communications or mass production. Other civilizations do not achieve advanced space worthy technology until after their planets are so old they can no longer support civilization. The only two other space faring civilizations I am aware of other than our own develop this level of advancement only after their destruction was imminent.

Consider that evolved intelligence does not necessarily mean advanced technology.

And those who do absolutely learn the benefits of silence. Who would master telemetry and neglect their own leakage?

We only assume everyone else must be like us.

And btw the “civilizing accord” is LAW. There are those who respect “law” and there are those who do not. Which are we?

Wouldn't predators have worked out how to fake-announce themselves, from a different solar system to ones they occupy, and then destroy anyone who approached it and revealed their home systems ?