We're only looking for our own technology
We've had radio for 100 years. How much will it be used 100 years from now? 1000? Even if there isn't something better than radio we haven't discovered yet, we're already getting better at aiming RF where it needs to go rather than radiating it wastefully in all directions like the typical FM/TV station does.
How much off planet signal bleed will the Earth have in 100 years? How much in 1000, if we're still using radio? Would there enough be enough that it could heard from thousands of light years away?
If we'd been looking for aliens 150 years ago, we would have looked for evidence of coal smoke in a planet's atmosphere...
Biting the hand that feeds IT
