My point is that much of what the city can tax has little to do with the city's GDP. Either the landscape of the city will have to change or the current taxation paradigm will have to change.
Again, putting $1B in some perspective, the LA Unified School District budget (which is county-level, so not directly comparable to the city, but anyway) is just under $19B. Maybe someone else can ballpark how much of that is associated to the city. Or look the other things that scale with population: police, medical, waste, social programs, etc.
LA is fine.
The city has a billion dollar deficit right now. Trivial for residents to afford ($83 per person), but difficult to actually implement politically.