Maybe we were already found and we are just being contacted right now, but we're still in the early stages of the contact, after all we know what happened when technological advanced humans contacted less advanced human civilizations.

Hence is quite reasonable our fellow alien visitor probably would be better than us at contacting very agressive cavemen with nuclear weapons.

Maybe we give ourself too much indulgency about how further we are in the technological evolution. Maybe we are just at caveman level +1 and looking for radio signals is like trying to find smoke based communications in NY.

Maybe we are still missing something fundamental about the universe and we don't know, like we ignored electricity or nuclear forces existed just decades or 150 years ago.

That UFO the US navy has in footage, from 2019, making a diving nose maybe at 200 mph into the ocean without making a single wave or splash, is telling you something: you don't know everything about physics, just yet.

But we can’t deny a natural barrier. Modern sci-tech if used in 18 century would dramatically explode into fundamental discoveries. Einstein Bohr et al would jump for joy having these “toys”, cause all they’ve had was basically pen and paper. But now sci-tech mostly supports existing theories for many decades. Not saying there is nothing new, but there is nothing groundbreaking either in fundamental parts of nature.