Sad, but the first thing my sci-fi mind thought of was whether Earth would be able to establish relations with a perhaps-society there without establishing military superiority first, just starting off with a Cold War.
Any planet harboring intelligent life would likely be several hundreds (like this one) if not thousands or millions of light years away, making any contact impossible at human scale. Even with this relatively close example of a possibly habitable planet, communications would take 1000 years to go back and forth.
As for actual contact... many earth civilizations would rise and fall before a spaceship going at even 2% of the speed of light could reach such a planet.
You're making the mistake of confusing totally unknown with very unlikely. We simply do not know enough to prognosticate one way or the other.
Perhaps every habitable planet develops life but only our plant has developed intelligent life. Perhaps only our planet among all the planet in the universe has life. Perhaps every planet develops civilization life and all such civilizations destroy themselves within about 10,000 years, leaving only hunter-killer robots.
In any case, interstellar space is so vast we couldn't practically other civilizations even if they turned out to be quite common in other solar systems.
Anything could be "The Great Filter". The best candidates for Great Filters are things which took a long time to happen on Earth (suggesting it may be a fluke or statistically rare event.) Conversely things that happen quickly, or things that independently happened multiple times suggest they aren't rare or unlikely events.
On Earth, high tech civilization appeared relatively shortly after humans evolved. Agriculture was independently invented half a dozen times in different places, and cities and civilization at least twice in the new and old world. We were also moving in the direction of science and technology even before we discovered coal power so the "other planets don't have fossil fuels" doesn't seem like a great candidate either.
It may depend on the availability on various natural resources, such as big (domesticable) animals, as hypothesized by Jared Diamond in "Guns, Germs and Steel". This is why native Australians were pretty much stuck in stone age era for thousands of years. They might have never developed beyond that level. Not because they're inferior, but because they had no means to start an economy capable of accumulating resources. One could easily imagine an Earth where the only continent is Australia (surrounded by oceans) and humans - even biologically identical to us - remain hunter-gatherers for eternity.
But I show add there is even a view with no "Great Filter" at all. That is the claim that life on the Earth has developed with a steady, linear increase in log-complexity whose zero-point is fairly close to the big-bang. And thus the human species developing now is developing about as early as it could have, as quickly as it could have and so there's no surprise that no civilizations earlier than us elsewhere exist even if we plausibly expect these civilization to be appearing now.
There are solar systems much older than the Earth. Evolution is definitely not linear. See punctuated equilibrium and mass extinction events. And there are millions of species on the planet. Evolution has branched many times. If that was true every branch should evolve in a similar direction at the same rate, but that doesn't seem to be the case at all.
Define much, earth is more than half the age of the universe. And another possibility is earth life came from off-planet - quite possible if life is common in the universe.
Punctured equilibrium is a good theory to explain particular species diversity and morphology. It may or may explain increases in complexity as such and there may or may not be a tendency for the various jumps to even each other out over time.
I'm arguing I know such a theory is true, just that things are so complex that no theory is definitive.
But even if you are correct, there could still be civilizations several millions of years older than us. Earth's history would have turned out completely differently if it wasn't for various asteroid impacts and geological events. The chance of two intelligent species evolving within a few thousand years of each other is pretty low.
Us humans, so self centered. What you say doesn't mean we can't send a probe that simply says hey what's up and you're not alone but probably are by the time you read this.
I'd be more concerned the aliens would be militarily superior to us, considering the millions to billions of years head start on technology.
Or that there are no aliens, raising concerns that most civilizations inevitably destroy themselves.
Or that there are, but they haven't made contact because they don't care about us. If they don't care they might wipe us out because they want our resources, or see us as a potential threat.
It should be possible to transmit radio signals between planets. Although it's possible we just aren't listening or they aren't doing it frequently enough.
Space travel is more speculative but it seems theoretically possible to reach a significant fraction of c even with 20th century technology. Even today's spacecraft could reach other solar systems in a few thousand years, which is reasonable on a geological timescale. If probes are self-replicating, or the mother civilization simply sends a lot of them, they could cover the entire galaxy in a few million years at most.
A radio signal would need to be extremely powerful to travel 500 light years without degrading (not to mention that even the senders may not be able to decode it after 1000 years :-)), and sending spacecraft to navigate 500 light years hoping it will perform all maneuvers correctly and not get hit by something in order to reach a planet without being able to send any useful information back seems naive and pointless.
If there's any space faring civilization out there, they're probably content with their own star system and maybe the ones closest to it - there are so many planets and asteroids to mine for resources (plus recycling would be a big thing) they could last for hundreds of millions of years...
Difficult yes, but neither of those things are inconceivable for even our civilization. Imagine one that's millions of years ahead of us.
Interstellar distances do prevent a lot of practical expansion, but it'd be nice to say hello to your neighbors, and start making preparations for when your star dies, or the even longer term heat death of the universe.
Or we don't try to contact them out of fear that they may be militarily superior to us and be inclined to attack us. And they don't try to contact us out of fear that we may be militarily superior to them and want to attack them.
People can be wary of new neighbours, i don't see why it wouldn't apply to space neighbours.
On a brighter note, maybe we should welcome with open arms anyone, after all, better be nice than not nice!
