Sustainable Slopes calls on ski resort owners to cut narrow slopes because they are more efficient from a water and energy perspective than wide slopes. From a business perspective, however, you may be correct.
It may be more cost-effective to cover a large bowl with fixed guns than to constantly move wheeled guns from slope to slope.
I agree with you that narrow slopes are a lot more fun to ski. They "narrow" your options and in so doing, improve your skills. Trails like OTW at T-line only give you about two-three lines to choose from under certain conditions. I like that!