I mean a lot of this all turns on what happens to us in the next 200 years. Which... That's slightly less time then federated America has existed.
Are we at the peak of what people achieve on temperate world's? Maybe technology doesn't meaningfully advance much beyond what we already know - you get a computing boom, Moore's law ends and then a couple decades of discovering no substantial alternatives to the silicon chip.
I've been homing in on this conclusion, or a neighbour of it for a while. Take the periodic table. That's it people, we already know all the stable elements. Nobody's going to discover unobtanium. Aside from some high energy physics and some details of quantum mechanics, we probably know most of the useful practical physic there is. The open frontiers are biology and chemistry, but those are all about combinging things we mostly already know about in new and interesting ways. Eventually we'll figure all of those out as well. Then what?
I'm not saying it's impossible we'll discover some amazing, paradigm shaking new physics that will upend everything. Maybe. But we can't bank on it and it's entirely possible no such civilisation shaping new physics exists.
If that's the case, then the future will all be about engineering based on parameters we already pretty much know. I often see the Daedalus project held up as 'proof' interstellar travel and even interstellar colonization are possible. That was a designs for a very modest space probe payload, but even so the resources required to build them would pauper our whole civilization. Even if, or when, we master the resources of our whole solar system, those probes would be a significant cost and it seems likely they're way too puny to deliver a robust self-replicating bootstrap infrastructure. There's nothing inevitable or necessary about interstellar colonisation. The universe doesn't owe us Star Trek.
Why would technological advance be entirely limited by the end of Moore's law? There's still advances to be made in biology, nanotech, materials science, and making full use of the computing we already have. And there are plenty of proposals for future engineering on and off world, if we have the motivation for those projects.
Agree. A space-faring civilization would have space ships perfectly adapted to their need for sustainability, and they can move to avoid any danger. We can also assume that well advanced civilization have mastered transmutation and that they might need access to planets only to get matter they can transform in whatever they need.
The motivation for traveling in space can only be to decrease probability of extinction and to increase their knowledge. The later may include studying other life forms and what they have learned. As a consequence, I assume they would specifically target solar systems with a high probability to host well advanced life forms. I don't give much credit to a random expansion in the milky way.
Regarding the Fermi paradox, the only paradox is excluding the UFO phenomenon as possible extraterrestrial manifestation.
You're not wrong, but, you have to admit that even if one is a highly advanced civilization, some planets are a lot easier to live and thrive on than others. I mean sure, we can TECHNICALLY settle Mars and live on there, but it will cost a lot of resources, the inhabitants will be constrained to enclosed spaces, etc. Even Antarctica is easier to live in despite its harsh conditions because you can step outside and not die from asphyxiation. (I'm mentioning that because the camps / settlements on Antarctica are probably the closest thing we have right now to a remote / off-world settlement).
If you're a spacefaring civilization, you probably don't live on planets to begin with. Terraforming is hugely energy inefficient, planets that fit the conditions to be comfortable for you biologically are probably rare, etc. Even ideal planets are incredibly inefficient when it comes to use of material.
You can support many times more people in things like O'Neil cylinders, bishop rings, etc. than you can on planets, using less resources. If you're the kind of civilization that can settle a galaxy, you're also advanced enough that you're going to care about that sort of thing, because you're already working on huge timelines, and you probably want to stretch your existence out for as long as possible. Being efficient with resources is going to be important there - the universe isn't making any more of them.
Are we at the peak of what people achieve on temperate world's? Maybe technology doesn't meaningfully advance much beyond what we already know - you get a computing boom, Moore's law ends and then a couple decades of discovering no substantial alternatives to the silicon chip.