There is: (https://www.universetoday.com/144108/a-brand-new-island-in-t...) it's just somewhat slow by human standards.

You can't make more land, but you can increase density by putting more units on the same plot of land. This is a totally natural way for cities to develop, but it's more or less illegal in the United States due to zoning.

There's plenty of new land in America and most countries. It's unused because it's far away from where people currently want to be, but that could change depending on what society and industry needs. Maybe remote work will somehow really last and push people out of cities so they can buy an otherwise empty section of wasteland.

Even within cities, it can be creates by zoning changes. My city recently relaxed density rules, effectively creating new land out of nothing in an instant. Developers are now building on that "new" land.