Three decades ago, men had very limited options when it comes to pants. For instance, at work, it always had to be slacks—which soon became boring and uncomfortable. It was only when Dockers came along and introduced khakis and the relaxed California style that men finally had another option—khakis, casual and comfortable, but refined, still.
Soon enough, different types of pants became available for men, allowing them to wear a variety of pants for various occasions.