If any change occurs, maybe they'll start in the high level events and later move down each year. Even if the thousands of older discs become "illegal" for competition, rec players will still use them. However, liability issues and peer pressure will reduce their use in unsanctioned play over time similar to how you don't see too many Aerobies used on DG courses. Those using "illegal" discs even now expose themselves to harsher penalties in case of accidents and unsanctioned events allowing them will likely not get insurance.