You can communicate with civilizations only at almost exactly your level.
Us, a thousand years ago, could not even detect any of our modern communication methods.
How could we expect to detect signal from a civilization a million years ahead of us?
It's not that intelligence is rare. Intelligence at exactly our level is rare.
This is said often, but there is no evidence for this. It's just a kind of cynical self-hatred.
A civilization that directly visits us, which would mean having some kind of interstellar travel, would be, yes, more intelligent. But we have no evidence of that. A civilization that has dispersed some kind of Von Neumann machine to watch over us, yes, would be more intelligent. But we have no evidence of that either.
I've seen a few (optimistic) calculations using the Drake equation that puts anywhere from 2 to 50 possible intelligent civilizations in our galaxy. Those are some seriously large error bars. Stretch this out into the total number of galaxies, then yes, I can easily see there being another intelligent civilization in the Universe. But interstellar travel is already difficult. I'm pretty sure intergalactic travel is more than "just a little bit harder." But to assume that it is likely that we are low down on the intelligence scale is utterly without basis. It's just as likely that we're the best the galaxy has seen thus far.
However, i agree that we can't communicate with primitive species, but it should be possible with more advanced ones that must have rely on electromagnetic signals. With that said, the problem I see is that our sphere of visibility is at most few tens of light years in radius and that assumes that the weak electromagnetic waves are noticeable at such distances even by advance technologies.
Though who knows. checking for radio frequencies might be a part of fundamental tests to any space faring surveillance systems.
It's all a bit airy-fairy I know, but having come such a long way in a mere thousand years - I feel like the ideas we have of super-intelligent beings may be primitive.
Further, the dyson sphere concept stemmed from sci-fi, or rather the human imagination. It seems logical to us that an advanced civilisation would build structures around stars to harvest their energy, but our logic is limited to the bounds of a few kilograms of grey, wrinkled biological matter.
The dog cannot understand the internal combustion engine. Alexander the Great wasn't thinking about the internet, or genetic engineering. We're quite sure of ourselves, and of what an advanced civilisation ought to be doing, and I think this is a mistake.