[rockfishroll]

I think your first point ignores one of the fundamental insights of the Fermi Paradox, which is that while space on an astronomical scale is massive, so is time. The milky way galaxy is ~100,000 light years across. So traveling at 1% of the speed of light, you could go end to end in 10,000,000 years. That sounds like a long time, but it's really not.

The earth is ~4.5 billion years old. So we can say with certainty that it's possible (not guaranteed) to become a space faring race (although not a galaxy crossing one) in 4.54 billion years. If we tack the amount of time it takes to cross the whole galaxy end to end we get 4.55 billion years. The milky way galaxy is 13.61 billion years old. That means the galaxy had 9.06 billion years worth of chances to churn out a another planet that could have expanded across the galaxy from edge to edge and been here waiting when humans arrived on the scene. Planets with Earth like conditions are certainly rare but my, admittedly limited, understanding is that they're not "1 in 9.06 billion years" rare.

There are obviously other constraints here. I think your second point about wealthy technological races potentially stabilizing at zero population growth is totally reasonable. But I think the fact that space's apparent scale doesn't actually matter is the whole reason the Fermi Paradox was such an "ah-ha!" moment for many people. The reason it's a paradox is that, given all of our assumptions for variable values in the Drake Equation at the time, it really seemed like we should have met some aliens. The point was that if distance wasn't the hurdle we thought it was in the equation as currently defined, then we were either missing some relevant variables, or we had made some bad assumptions for the ones we had.

[saiya-jin]

> wealthy technological races potentially stabilizing at zero population growth

It doesn't have to, in fact (relatively) endless population growth is the prime force to push even lazy non-curious fearful aliens out of their planet and sun. That and obvious unavoidable necessity of every sun eventually becoming killer of its own ecosystem, even if their planet would be super duper stable with all meteorites under total control.

The rest I agree with, even civilization having mere 100 million years of advantage on us would be able to properly colonize non-trivial part of milky way by now, we just have to abandon star trek/wars expectations of instant communication and travel which is fine. We humans are generally pretty bad at grasping true meaning of numbers when it comes to ie astronomy.

[joe_the_user]

The problem with any overpopulation or growth-limit push argument is that since interstellar travel is a very, very difficult to achieve, there's no reason to expect either humans or aliens to achieve interstellar travel at the point that they've encountered some limit to a process of out-of-control growth. Space colonization is certainly not going to solve global warming, etc.

Indeed, if human society is a guide, a society that develops interstellar travel would have to have reached a stable situation, so stable I'm not sure if massive expansion would seem desirable.

[joe_the_user]

So traveling at 1% of the speed of light, you could go end to end in 10,000,000 years. That sounds like a long time, but it's really not.

Human have no way to survive that time period, no way to create a self contained environment that would survive that time period and no civilization that's lasted a fraction of that time. The increase of human technology hasn't correlated with stability so increases in our technology don't seem like arguments for our ability to act in a long and large scale, despite being implicitly taken as such by a lot of people.

Sure, in the geological time humans study ten million years isn't much but the claim that a living creature could act in the time period is purely speculative. Speculation is fine but the rhetoric of the "Fermi Paradox" is "why don't I see of things I have only wildly speculated about, there's something weird here", which is kind of problematic.