Isn't the real great filter the speed of light? How long would it take us to go even to the nearest solar system, and even at say half the speed of light, let alone to the next galaxy?
You'd need to form some sort of a cult, and some sort of a space mini-town, and somehow reproduce food in space, and have some sort of renewable energy.
We haven't sent humans to even Mars yet. Rather than 'they would have visited if they exist, and since they haven't there's a great filter,' it's probably more that we just don't know what the limits are and there's no reason to think hard constraints like the speed of light can be addressed even in a million years.
You'd need to form some sort of a cult, and some sort of a space mini-town, and somehow reproduce food in space, and have some sort of renewable energy.
We haven't sent humans to even Mars yet. Rather than 'they would have visited if they exist, and since they haven't there's a great filter,' it's probably more that we just don't know what the limits are and there's no reason to think hard constraints like the speed of light can be addressed even in a million years.