Well, Frank,
I can't second-guess people for building lavish churches. If people are forced to build lavish churches, that's another matter. Oftentimes, poor people build lavish churches and other public buildings as a matter of pride, showing that they too can build and possess something beautiful. Many times, such buildings provide a place of employment and an outlet for artistic expression and a community gathering place and education center - and you can't eat any of the materials used in building a religious edifice.
-Joe-