In many states, including Nevada, subs don't have to have a four-year degree to substitute teach, and the lousy pay reflects that requirement. However, it isn't any better in areas such as Oregon where the pay is much higher because what happens is there is a glut of people on the substitute list making it virtually impossible to support oneself on the pay. You may work three or four days in a given week, and then you may not work at all. Furthermore, in many school districts, retirees are allowed to double-dip as substitutes while collecting pensions, and they are allowed to have "first dibs" on any assignments.
The problem becomes extremely acute because most school districts use their substituting teaching pool as a hiring pool for regular teaching jobs. It's a weeding-out tool. In southern Oregon, you may have to substitute three or four years in order to land a regular teaching gig.
Unlike Nevada, in Oregon, if there are long-term sub assignments, you have to bid on the open market for them as you would a regular teaching job. In Nevada, the long-term gigs are filled the same way as the short-term ones.
I see Washoe County School District hasn't raised its sub pay for close to ten years.