For two reasons I think. ONe is civil diobedience. Gun owners ignored the form, filled out wrong information and I am sure other creative ways. WE WILL HAVE TO HAVE A PLAN OF CIVIL DISOBEDIANECE.
The other reason it failed there is the incompetence of the liberals who designed the plan.
One of the things our Canadian cousins did was fill out 20,30 or 40 forms for each gun altering the S/N on each form. This choked the system and threatened to crash the system.