It’s the TIN (photogrammetry). As you’ll have noticed, world updates always include 3D cities, it’s a major selling point of the sim. Imagine if they did a WU Brazil with a few POI, updated satellite but no photogrammetry. Maybe a small section of the user base would be happy but in general I’m sure there’d be an outcry.
To get the photogrammetry they need to fly specially equipped planes over cities at low level in effectively a search pattern. Often they have to use local companies for this, which is probably one reason why the TIN is of such variable quality between WU. Therefore they need local companies with this capability, and approval to fly these routes.
Three was a good discussion on this on the last dev livestream which you can read below. It’s too long to paste here. Scroll quite a long way down until you get to the heading “Availability of Data in World Updates” or you could watch the video of preferred.
I will take one quote from there: “I’ve been trying to do what needs to be done to get Brazil 3D cities. It even went as far as me thinking about creating a new company, renting our own planes, buying our own cameras” which illustrates the problem.
We all want South America, Africa, and lots more of Asia, but it’s just not always possible.
It’s not all bad news, Jorg’s piece above ends with some better news about Brazil.