Exactly, just as if we were able to listen to everything instantly- could we detect anything sent in the past or future? no- only what was being sent right now!
Again it's precisely the same either way , it's a total wash isn't it? for every time/place we'd miss in one scenario- we'd gain one in the other
and either way- the galaxy is billions of years old- yet only a 100kly or so across... so that time slice represents very recent history either way.
The observation of the great silence is not proof, it merely supports the mathematical improbability of ET
The universe all came from the same place, a wide range of possible environments can be found right here in our solar system. Even right here on Earth, in places where conditions are not quite right, even surrounded with teaming complex life- none has even adapted, far less originated and thrived in our own inhospitable environs. FAR less intelligent beings
Consider that we are the only one in MILLIONS of species to achieve this. and only through extremely improbable circumstances. i.e. we could find a million planets identical to Earth, and expect to find dinosaurs, if anything more likely than humans- and that is generously granting you abiogenesis on all of them as 100% given
The universe just isn't all that big to cover the odds against ET
And once again, colonization is a logical step, certainly Hawking's sees it as our destiny- at least it's conceivable after a mere century of powered flight- yet not one single other civilization ever achieved likewise?