First, you'd be surprised how many people we can support. Like we could likely support more than a trillion people on Earth. The population of a full Dyson Swar

First, you'd be surprised how many people we can support. Like we could likely support more than a trillion people on Earth. The population of a full Dyson Swarm around our Sun likely caps out in the quadrillions, possibly quintillions. Second, it's entirely valid to ask the question of whether we'd ever reach such populations. This is of course unknown. As a solution to the Fermi Paradox, the idea of reaching a steady state (or even shrinking to a fragment) seems unsatisfying as a 100% outcome. Once again, it only takes 1 to keep growing and become detectable. A lot of things are likely to change in the next millenium, for example: 1. I expect we will live much, much longer than we do now; 2. Automation will increase to the point where labour is highly unlikely to be the limiting factor in any kind of industrial output. That leaves resources and energy as the limiting factors. Well, resources are just a proxy for energy. There are several rocky bodies in the Solar System that could, given enough energy, provide unimaginable amounts of raw materials; 3. Despite the wealth of developed nations, we are still living in an era of relative resource scarcity. Individuals in developed nations are certainly generally more prosperous than those in developing nations but it's expensive to raise children in developed nations the way most parents want to raise them: paying for education, housing, etc. I'm not comfortable making the prediction than the modern trend of having relatively few children per individual in the developed world will continue into an era of longer lives, far more abundance and being freed from the need to work their entire lives to set up those children. Lastly, there are some very obvious applications for huge amounts of energy, for example: 1. Extracting resources; 2. Vast amounts of computing power. What would you do with this? We haven't been good at predicting this other than to say that more bandwidth and more computing power has thus far always found applications that people want. One obvious one is I suspect we'll have VR worlds that people will basically live in on a scale we can't possibly yet imagine; 4. Interstellar travel; and, of course 5. Cryptocurrency mining. :)