The story told in America, and most of Europe is that humans evolved to be really smart, and we have built the most advanced civilization on the planet.
Even those who believe in creation, still believe that we are the most intelligent / advanced. Or at least, do not question it.
This belief is so deep that archaeologists and anthropologists ignore many things they dig up. This practice comes from on-high. You don't get to be archaeologists if you buck this.
We are purposefully being held back by some group, and we, humans, seem to just go along with it. (because we like to imagine ourselves as the most intelligent?)
If we don't see it, it doesn't exist
It is good to be sceptical, however, humans have tended to be overly sceptical. "If i can't see it, it doesn't exist." And no one is more sceptical than those who live in ivory towers. (often to defend their position in said ivory tower)
Although we often have lots of evidence for something, long before we develop a way to see it, the old stodgy scientists disbelieve it. Things like radio waves, microbes, atoms… were all stodgedly denied existence until we had ways to prove they existed, to see them.
We even apply this to aliens. So many UFO sightings, so many stories of abduction, so many other encounters, and we still, at least officially, do not believe in extraterrestrial aliens.
We believe that what we discover, a more advanced species would have discovered
This is really anthropocentric, that we think that our way of thinking is the way of thinking. But, there are all kinds of forks in our technological progress that could have changed what / how we think of science and our world.
Take the airplane. What a weird invention. Thousands of years people have looked at birds and thought of flying. The Chinese had kites, often really big kites. Da Vinci made many sketches of machines that could fly. So, why did the Wright Brothers build an airplane at Kitty Hawk? This is only weird if you know about other, previous great civilizations, and how they had levitating ships. They discovered levitation, and i do not know if they ever worked on aerodynamics.
Levitation is actually extremely simple, and it is amazing to me that we haven't reinvented it this time around. In fact, there were several times we discovered it, and then relegated it to the back of science text books. It is like, Newtons idea of gravity must be defended at all costs!
We could be using vacuum tube technology in our computers, except we decided, like, all at once, to use semiconductors. Semiconductors were around before we invented silicon doping. Electronics people would go rock hunting. Using metal probes on rocks until the found one that by chance was formed in the right way, and was a natural semiconductor.
We now have digital computers, and the analog computer is almost forgotten.
There are so many points where we decide to go one way and ignore the others.
And we still think that we know all of science, explore all areas.
However, to me, it is really shocking how many doors we have closed to get to where we are today.
Why do we think that advanced aliens would use radio waves?
Tesla / Marconi worked out broadcast voice over EM waves. Telephone, Radio, Television all of these are along the same line of thinking. And we think that this was a natural progression. And, of course, any bright aliens would think of the same things, in the same orders as us.
However, this is not true. We could have worked out how to make fiberoptic cable much earlier. It is just a process of making ultra-pure glass. It is actually quite simple. Instead of putting up wires for telegram, we could have been stringing fiberoptics. Our current time would look very different if we went down that path instead.
Similarly, if we continue on aether research, we would have found other forms of transmission besides radio waves. However, the blind acceptance of the Michelson-Morley experiment shut that down.
There many other modalities of communication. And we have been moving away from radio waves for quite a while. Many people are finding that 5G is very destructive to humans, and as we explore that, we will find that having so much noise in the EM spectrum is not a good thing. As we discover this, and its ramifications, we will work more and more to eliminating radio noise.
In another 100 years, i am sure that the Earth will be radio silent. So, our idea that any advanced extraterrestrial race would be broadcasting radio waves for us to pick up on, it really weird and anthropocentric.
We don't know, what we don't know, and so it becomes quite easy to think we are seeing the whole picture, when there may be seeing just a small fraction of it.
There may be (there is) many colors that we do not see. Like there are color bands above or below the rainbow we currently see. (there are people who see more colors, and say that there are) But, most people do not even think that there is something there.
There is a huge amount of our world that we do not see. Do not interact with consciously. And even with many tales of their being more, people tend to not believe it.
Humanity fails to see things on all kinds of levels. We have a size preference, where we barely see microbes and storms, but we do not see any bigger picture or smaller structures.
We have a time preference. There are beings who live in between the flickers that we call reality.
We have a light-wave preference. We tried to see things in other bands of EM, but we don't really. A psychic often talks about silver and gold light. But, science hasn't see it yet, and believes it doesn't exist.
And this isn't even talking about all the stuff that we just plain ignore. That science has decreed that it just doesn't exist.
Meeting with aliens, that will happen in the near future, will be a very eye opening experience.