The abortion debate hasn’t been “won” by any side but the pro-life side had been winning and probably hit their high water mark with the ban on partial birth abortions. They probably jumped the shark with their whole “life begins at conception” kick.
By all reasonable measures, the gun rights activists had won the gun control debate.
What is it that the NRA was advocating for that they had not gotten? I can buy any number of semi-atuomatic handguns and rifles over the counter with proof of residence and a quick electronic background check. I can get magazines that hold hundreds of rounds. Noone other than the gun store knows I have the gun. I can buy at gun shows with even fewer restrictions.
I can buy a gun that fires bullets the size of steak knife blades that can stop a car or crack a cinderblock.
That doesn’t mean the debate can’t be reopened by events like Sandy Hook. but before Sandy Hook the chances of even symbolic gun regulation was practically nil. The gun rights lobby had won and had started becoming a partisan organization supporting other issues.