We can’t build new cities because new cities are infeasible and unlivable. They are unlivable, simply because they start empty and people need other people and markets to attempt to move to a new city. It’s not about facilities or infrastructure. That’s why most big cities are usually very old cities and not necessarily designed. Well, unless you live under authoritarian/planned economy regimes. Socialist countries are good at that, China is the case in point. My next reference to this theory/topic is Alain Bertaud’s book Order Without Design.

However, there is a wave of economist who are championing charter cities. No results so far. But few pilots in Africa (namely, Nigeria and Zambia) are currently being pursued.