This is a huge map, right? I usually have about as many settlers and cities as you have tanks by that time, and twice as many infantry. But take that with a grain of salt, as I play with a mod that reduces corruption to a manageable level and allows better units to win on occasion against lesser ones.
I may make the mod available, as I'm just about done playtesting it (over the course of several months - I don't like doing things half-baked). It's pretty well balanced, as long as you keep up in tech. I don't know about some of the extreme strategies, though.