As a gross generalization, there are probably two ways in which one can approach the building of a new building. The first is based on demand. You believe that there is demand for new housing or new office space or some other use, and so you decide to build new space in order to satisfy that exact demand.
Sometimes developers get it wrong and build too much space or the wrong kind of space, but the reason for building remains the same: you believe that there is a market waiting for you.
The second way to build is to completely disregard the market and just build whatever you feel like building because it is going to serve some other alleged purpose. And that is arguably what is happening in Saudi Arabia with The Line and what happened in places like North Korea with its “Hotel of Doom.”
I suppose that there is a chance that somebody in North Korea believed (or pretended to believe) that there was demand for a skyscraper that was 1,000 feet tall and housed 3,000 hotel rooms, but in reality, the real reason was that leadership thought it looked cool and that it would make for good propaganda.
To be fair, there was probably also some hope that it would spur demand and attract foreign investment. But it’s still a case of just building whatever you want.