They want to build infrastructure, but since nobody owns the land they're squatting on, there's no way to raise money via land taxes. The technocrat answer to that would be individual septic tanks and solar panels, but because there's no land ownership and no law enforcement, you'd have to be nuts to invest any serious money in building a house, because a gang would just take it from you. Classic development trap.
Jonathan Katz talked about Corail/Cannan in The Big Truck That Went By, and he wasn't positive. https://www.amazon.com/dp/B009OZN6GM/ Published in 2013, but it doesn't sound like much has changed.
1: Port-au-Prince gets about twice as much rain as Seattle per year, and is routinely hit by hurricanes. If you don't manage the stormwater, it washes your house downhill. Sewage systems have also become important, since UN peacekeepers brought cholera with them after the earthquake.