You are correct. It is get it while you can and everybody does it.
The people who sit in negotiation, look at the numbers, see them as unworkable, then make the deals anyway should be held criminally responsible. If the union members can’t accept a feasible deal then they can go on strike.
One advantage Detroit has is the fact that its legal for private industry to compete with municipal services in most cases. Its why the Detroit bus company is growing as the city bus service is shrinking. Its also the reason for the fight over water in Detroit. The water department is becoming increasingly privatized and they need to eliminate debt to attract more investors.
I live in Jackson county Michigan. In the city of Jackson they forced through a law that drove competing trash pick up services out of the city and imposed a tax to pay one service for all. Fortunately the people killed it within 6 months and went back to choosing their own pick up service from many.