We already have the technology to move a planet; it's just orbiting rockets. (Ion thrusters are especially promising here because of the small amount of mass you lose from the planet in the process.) We just don't have the necessary industrial scale to supply enough rockets and energy. A planet-sized space station is almost certainly possible with carbon nanotube ropes, but those have not yet been demonstrated to work in practice.
However, smaller O'Neill-cylinder space stations are feasible even with just steel cables, and I look forward to a future where the vast majority of inhabited land area is in such contraptions. It will take at least 30 years, probably more like 300. The danger is that we collectively take a more destructive course.
> It will take at least 30 years, probably more like 300. The danger is that we collectively take a more destructive course.
I don't think there is a clear trend toward this goal at all.
Extrapolating current trends, we are fairly likely to peak in total population as a species long we become space-constrained on earth; more remote living space is pretty cheap in basically every industrialized country right now, and living in a conventional house in the boonies is like ten orders of magnitude easier than making anything extraterrestrial work (neither climate change nor even global nuclear war is enough to flip that).
Sure, people might like the concept of space colonization, but we're not seeing significant amounts of people living on boats in the Atlantic, so I would not expect to see people living on spaceships within the next centuries, either...
Be careful to note that I didn't say the majority of people would be living in space colonies, but that the majority of inhabited land area would be found in them.
Probably you're right that most people will choose to die on the same planet they're born on. Most people today choose to die in the same city they were born in, and most coconuts sprout, if at all, within a few meters of the tree they fell from.
That doesn't mean that coconuts' ability to float across the ocean is inconsequential to coconut species distribution. It only takes one coconut making landfall on a barren atoll to start a new coconut grove.
There are, in fact, a significant number of people who live on boats. There would be many more if the boats weren't dependent on docking to refuel.
It's a mistake to extrapolate from current trends when it comes to exponentially growing phenomena. In April of 02020 covid had killed less than 1000 people after six months. In 01770 two million years of human beings had managed to speed up their transportation from the speed of a marathon runner to the speed of a racehorse. You have to look at the underlying dynamics, and even then what you often learn is that the future is very uncertain.
I do absolutely agree that extrapolating population over more than a few decades is basically a cointoss, but I still thank that exponential growth is far from certain: Basically every industrialized nation has negative population growth when excluding immigrants right now, and this is very much a global trend.
I like your optimism and would love to see colonies in space, but I think it is overly tempting to consider settling space akin to European colonization of America, when it is more similar to settling on the high seas/Antarctica (right now)-- technically feasible for decades or even centuries, but not really happening simply because of lacking incentives (and the incentive structure looks sadly even worse for settling in space than either of those to me).
However, smaller O'Neill-cylinder space stations are feasible even with just steel cables, and I look forward to a future where the vast majority of inhabited land area is in such contraptions. It will take at least 30 years, probably more like 300. The danger is that we collectively take a more destructive course.