WindDancer
THE LOOSE CANNON
For the inspiration of Gotham City the creator Bob Kane got the idea from cities like Chicago and Pittsburgh. Over the years writters shaped Gotham city to resemble New York. But originally Gotham city is a darker and more sinester reflection of Metropolis (which is Superman's turf) Both cities have certain similarities but it is believe that both cities started equally the same (Economy). Over time Gotham became more corrupt and more criminal than Metropolis. The city of Gotham wasn't totally lost do to contributions and good will of Thomas Wayne and his Multi-million dollar corporation.
Historically (in the comics) when the depression occur both Metropolis and Gotham were thrown into poverty. I don't know exactly how Metropolis manage to pull itself out of the depression but Gotham didn't recover. Around that time the murder of Thomas Wayne and his wife took place. And as you see in Batman Begins the greedy CEO's took over the business and complete discarded most of Thomas foundations to the poor. Causing an even bigger catastrophe for the economy of Gotham.
Because of the many writters in the comics and the movies, and the tv shows there hasn't been a perfect picture of Gotham city. For me the best illustration of Gotham city can be seen in Detective Comics (which is the title I'm subscribe to. 😛) and a more corrupted and darker illustration of Gotham can be seen in Legends of the Dark Knight. Which in a timeline is connected to Batman: Year One by Miller.
Well, don't take me word for word this is pretty much my opinion. Fans will have different responses so I hope my helps in some way. 😄