Your number four is the real reason for the problems. The number one priority of the metro system is not to transport people from place to place. Its to provide as many jobs to a certain demographic as possible. Maybe half of the people who collect a paycheck there contribute nothing. Fire them, and they will have enough money to perform maintenance.
I noticed on my last vacation trip to DC that a large number of workers at federal museums, monuments, etc are seriously obese black people.