Why would they build? They're losing members year over year in droves. My parents are at that unfortunate age where a lot of friends and family are starting to die, and one constant refrain in the area is "when can the funeral service be? will a priest even be available at the church that day?" My grandmother died recently and they had to wait for a day for a priest to be available at that particular church because he holds Mass at three different physical locations in the area due to a lack of faithful. And this is Southeastern Louisiana, which is about as Catholic as it gets.