It seems likely that one civilization will be the first to become technologically
advanced, enabling detection of other life. We could be that civilization.
It could also be that it takes a very long time for 2 civilizations to be advanced
enuf & close enuf for one to detect the other.
Well, one assumption of Fermi's that leads to the paradox is that civilizations survive for millions of years.
Our species is about 150,000 years old, we have had agriculture for about 10,000 years and have had radio for just over 100 years. I've yet to hear anyone confidently claim we will be around another 10,000 years, let alone 1 million.
This also ignores the economic aspect of travel to other stars. For example, at this point in time, we have sent a couple of probes out that can get to other stars *in a few tens of thousands of years*. The likelihood of those probes actually being found (once they are radio silent) is pretty much zero.
To actually send a probe out that will collect information and return it to the source in a reasonable amount of time is a HUGE problem. Getting to speeds close to the speed of light takes a *lot* of energy. Lower speeds simply won't get the information back before the society changes. And such energy resources will be valuable no matter what species we are talking about.
So, until there is a LOT of extra energy produced by their society, it won't be economic to travel in any real way to the stars *unless* they also figure out how to *automatically* search and mine asteroids and planets and have everything done by automatic probes.
Again, not exactly an economical thing to do directly, although there are clearly economic advantages on shorter time periods.