It's not that simple. Rapidly increasing the housing supply has all kinds of effects on communities:
* Decreasing the value of nearby homes (supply and demand)
* Increasing traffic and strain on community services like schools
* Environmental impact
* Rapidly changing the demographic and possibly culture of the area
Zoning laws and the permit process exist to help ensure safe buildings but also to help protect the home value of existing residents.
This makes sense in communities with the infrastructure to support it though and we definitely should be looking into ways to safely house everyone.