Government missed their opporunity to ban all firearms (outside of specific regulated circumstances) in 1934. America was a different place back then. Communists were making up ground, lots of displacement and misery, capitalists were seen as the cause of the depression, the media was closely allied with their perferred politicans, and the politicians knew that they had blanket license to dramatically expand the role of government. No politican will ever resist increasing their own power. The term "New Deal" is not an accident. It refers to a new social contract the public would have with government. To show you how severe this was, handguns were damn close to being NFA items.
America never again has come close to the brink of being desperate enough to "need" yet another 'alternate' social contract with government.
This being said, the AWB fight is only being continued by the antis because they've lost all other battles, and believe they can temporarily withdraw from the political fight honorably if they have a victory. They can't touch handguns and federal handgun registration schemes are laughed at, but people still have this thing with the term "assault rifle", even though rifles fitting this description are rarely used in violent crime. Thus, they believe they can win this one, and deliver a victory to those who have been funding them for years. Without it, all hope is lost for them... They aren't going away, but can be pushed into the fringe like ardent US Communists. Unfortunately, they'll come out again when they think they can successfully push their agenda.