I think it has to do with it being only for handguns and not for other weapons. At some point, they changed its terms and it caused conflicts with recognizing other states and required extra work on teh part of the Atty General’s office. I know, at least when he was just contemplating running for Govenor, Jerry Kilgore sent some signlas that he intended to reach as many agreements with other states as Florida did while he was AG. For some reason, that didn’t occur.
At least, thats what I recall reading. VCDL can probably clue you in further.