The more people start using cards for points and miles, the worse it is going to get for Amex. Chase Club offers 1.5 miles per dollar, Citi Prestige offers 3x on travel and 2x on restaurants (is $100 a year for Citi Gold account after $250 airline reimbursement), Virgin Atlantic offers 1.5 miles per dollar plus bonus after certain amount of money spent, same with some of the hotel branded cards. It's getting harder and harder to justify getting an Amex Platinum besides the benefit of accessing Centurion lounges and even in that case, most likely one have a combo of cards to max out points.