If civilizations are common then there are just as many less advanced civilization than us than they are more. Heck if technological progression leads to the downfall of a species than by default everyone we should be seeing is around our own level of development if not lower.
If intelligent life is an anomaly then it can be very well be that in the life span of an existing civilization they would be the only intelligent one in the galaxy or even beyond that and they would simply die out even 1M years is a blink of an eye for universal time scale.
And lastly regardless of what the civilization is today if they are on the other side of the galaxy we see a 100,000 year snapshot if they are in say another galaxy even a close one like the Andromeda galaxy we see them as they were 2.5M years ago.
Tight-beam, tachyon transmission, quantum entanglement with retro-causality suspension or w/e they might be using if they are so advanced beyond us that we look like anthills to them is fine but at some point they were just as advanced as we are and less so that's the noise that we should be hearing and we aren't.
If the period of time before all high-power communication is encrypted is short, then the likelihood that the period of our ability to pick up unencrypted high-power communications will intersect it is potentially very low.
The universe is _huge_. Most of our communications will not be audible above background radiation after a little way out - this could be no different for any other civilisation's communication technology. You don't use a nuclear reactor to power a cell tower, and if you don't put that much power into it then it's not gonna be detectable ten light years out.
http://www.planetary.org/blogs/emily-lakdawalla/2012/3390.ht...
There's so many assumptions that they'll basically use a version of modern technology but bigger in the "why can't we hear them?" question. Tight-beam, fully encrypted data with sensitive receivers could easily be utterly undetectable by our understanding.