However some expenses are hard to reduce. When you promise someone a pension of $X/month, you can't just stop paying them that, even when you lose half your taxpayers, and the property values of the other half take a dive.
If you build a man a fire, he'll be warm for a day.
If you set a man on fire, he'll be warm for the rest of his life.
It's been a continuous march where the local govt seemingly just ignored the issue
A big reason why the city is taking in less revenue is because they have lost a big part of what made their workforce middle class. They have now replaced a lot of lost jobs with low wage jobs that further eroded revenue and then you have people leaving the state to find work which further eroded revenue. You also have a host of other issues that involve corruption of politicians who did not properly fund pensions and handing over public municipalities to private interest on a silver platter. Now poverty and crime has gone up and they can't even fund police to respond to it. And, then you have that problem of the city's hundreds of millions of dollars in unpaid taxes.