People have been releasing large numbers of reptiles(large and small) and many other animals into all of fla. for a very long time. My guess is was done in large numbers since the mid fifties.
South Fla. Has and is the home of mass imports(all kinds of animals). And the cages are way better now. In the old days, chicken wire was the norm. The animals did not have a cost, so no one cared what go out, as long as more came in.
I think the problem is not the released animals, its the strenght of the habitat. In those days, the wild areas were vast and WILD. Now they are merely remnants of the habitats they were. So invasive animals are now getting the edge, AS TO BE EXPECTED.
In my humble experience, ferals and invasives in fla, have nothing to do with New York City, or any other big city. They have everything to do with the mass amounts of people and habitat destruction. Cheers