A) People never pooled their intellects to kill for religion. It's like saying "People have been chipping in money to buy pizza for their friends for decades, why can't they pool it and feed the Third World?"

B) As you just stated, paper money is meaningless. In fact, all wealth is meaningless except what you can use yourself. You only truly own what you can carry with both hands at a dead run (I think that's Heinlein, but I'm not sure). The idea that people will force you at gunpoint to repay your loans with property is ludicrous. If society has collapsed to the point that currency is worthless, anyone with more guns than you can take what they want.