"Even today, the need for work is a common reason people move to urban areas."
This sentence, although not inaccurate, is not necessary in order for the rest of the paragraph to be coherent. The sentence states that nowadays, people continue to move for work. However, the passage is not a comparison between the past and the present. It simply wants to inform us of the changes that led to bigger cities. Therefore, you can remove this sentence without seriously altering the author's explanation.
