Maybe that is the filter. If your society hasn't figured out the tech to do it efficiently, the rest of the galaxy doesn't care about what you have to say.
I've always been a bit confused about the idea that an advanced civilization would be uninterested in us because we've "only" reached the ability to communicate via radio waves. We're either a threat or an ally to these other civilizations, and if you were them and you detected a society that was clearly on course to eventually catch up, it would be in your best interest to treat them like one of those things ASAP so you can have a hand in their development.
To me it feels most likely that our signals just have not had enough time to get to them.
I think the "dark forest hypothesis" can apply here.
The advanced alien civilization may indeed be interested in us, but still not consider it their best interest to act as soon as possible.
If they decide to act, other civilizations (perhaps even more advanced) may decide to intervene in some way. A civilization that decides to reach out (in a friendly or hostile way) also reveals their own location in the universe.
The most risk adverse choice is probably to remain quiet, especially if they are millennia ahead of us technologically.
To me it feels most likely that our signals just have not had enough time to get to them.