Not to say that no city could field huge armies on it's own. Ever. They used funds from allies/suboordinates to do so. For example, Athens, even though she was a quite prosperous city during the Persian Wars, could field about 10,000 male citizen hoplites plus several thousand light troops at most, and that with help of surrounding cities and villages, as well as an extensive farming system stretching around the region of Attica.

Maion