Definitely many lines are using thinner greige goods. But the width is the same
All one has to do is pull older fabric of the same line and compare the weight. The newer greige goods are noticeably thinner. This saves on manufacturing and on shipping weight. However, the width of 42-44 inches is the same due to the looms/machines that the yardage is made on. The expense of narrowing the width of the machinery would not be cost effective.