Earlier quoted context omitted.
Part of the reason these are so captivating is that they are slowed down instead of real time. This gives them an other-worldly quality where you can see extreme detail but in a different motion than you would normally see it.
Many of the cityscape ones I don't believe are slowed down, at least the ones I have seen. If you watch the movement of traffic it appears to be moving at normal speeds. Even the orbital ones appear to be real-time. The otherworldliness of the video seems to come more from the smoothness of the motion and the uncommon perspective. Because many of the scenes are captured with drones instead of helicopters or airplanes…
They definitely are massively stabilised though and Apple used to update videos from time to time, tweaking stabilization, colors or sometimes length and pushing new versions. They haven't done that in a long while though.
Some seem shot from fairly high altitude and may use planes instead, and at least for some videos, I've heard they used 3rd parties to shoot them.