It seems large entries are partly due to clubs needing the revenue to cover the cost of putting on the trials, maintaining grounds, etc...
The clubs are hesitant to having Specials or Restricteds as it would obviously reduce the number of entries and income.
Another concern is of course whether or not the club persons actually putting on the trial would have dogs that could run with the necessary qualifications for a Special or Restricted.
One way to help make that decison to go to a Restricted would be to raise the entry fees to cover this loss in revenue.
How much would you pay to run a Restricted ?