It has been estimated as recently as 2011 that the value of property owned by churches in the US could be as high as $500 billion. Think of all that as a large city with 2.5 million single family homes each valued at $200,000.
Assuming a taxable value of $250 billion and a tax rate of $3000 per $100,000 of taxable value, the revenue lost to local taxing authorities would come to just $7.5 billion.
Local government revenues in the US in 2011 came to $1.2 trillion, so the revenue lost to churches' property tax exemption comes to a measly 0.6% of that.
Big whoop.