St Louis is a physically small city that has lost well more than half of its population and probably 3/4 of its tax base in the last half century. It has been dangerous for a lot longer than the last couple of years. Because it is so small, rival gangs are all crammed together in very small ‘territories’, so disputes are constant. There are nice parts of the city, but one wrong turn and you’re the Griswalds trying to find a way out.
The 1876 vote to separate from St. Louis County was one of the dumbest ideas ever. The city didn't want to pay for services in outlying areas. Apparently nobody foresaw the later growth of suburbs.