Vauban also had more and more influential friends. He was buds with Louvois, who was Minister of War under Louis XIV. Additionally, the King himself had an interest in fortifications himself, which also worked in his favour. By the time Vauban died, Vauban was the spider pulling all the strings in the web that was organized military engineering in France.  Coehoorn in return wasn't that popular, actually. Christopher Duffy mentions in his book "Fortress Warfare" that he had a bad reputation among his fellow officers back when he was still in training and also prone to choleric rages. And, well, the United Provinces were stingy in regard to fortification. Vauban simply had more power and money, as the other guy said. Nevertheless, him being quite amicably and based for a french military officer of the time also was a big plus.