Antidisestablishment, I think you've got this backwards. I think that heavy taxation has crowded out a lot of charitable giving, including giving that would have gone to the churches, and that the government programs have crowded out church programs.
How nice that American church didn't have to deal with those distasteful poor people! They could focus on important things like building grand cathedrals and growing mega churches and even sending missionaries to poor countries instead of dealing with the filth in our own streets...
I don't see a taxation clause in the church's mandate. The church, as a whole, has sold their collective souls for tax exempt status. The funny thing is churches are automatically tax exempt. You don't even need to file for 501c3 status. The only "advantage" to this is the protection of assets for church officials.
There are still many individuals and churches working in the field, but, as a whole, the Church has little authority left in a sphere that is rightfully hers.