There are a few reasons why associations will not set specific criteria for registrations.
1. DIVERSITY - Genetic diversity is a good thing in any breed. This diversity is what allows the same breed of cattle to be raised in lush green pastures of Iowa, to the mountains of Wyoming, to the deserts of New Mexico. No one kind of cattle works in all environments. Plus, just have cattle have changed over the past 50 years, they will continue to change. Genetic diversity is what will allow these changes to happen.
2. ACCURACY - EPD's are only as good as accuracy of the person submitting the data. For the most part, EPD's are founded around the honor system, so establishing a threshold may reduce the accuracy of the data on cattle that are below or on the bubble of being able to be registered.
3. MONEY - Breed associations are looking for ways to register more cattle, not less. The more registrations means more income for the association, and like has been stated earlier, many of the associations are not in the best financial shape, so reducing registrations is a touchy subject. This is the same reason why many associations were slow to address the issues of genetic defects. Tough rules could have been put in place to eradicate many of these defects, but these tough rules would have reduced the number of registrations and would have impacted the association's bottom line significantly.