That depends very much on how you define government. If you are a band of hunter gatherers does the "Chief" or "Shaman" that your band looks up to for leadership count as your goverment? If the answer is yes then there were way more governments in the past than there are in modern day.

If the answer is no then your point stands. However I tend to think that the answer is in fact yes and the trend does indeed seem to be toward centralized world government given a long enough time period.