I think a big factor in the disappearance of support for gun control is generational, namely that subsequent generations don’t harbor as many racial and xenophobic anxieties as previous generations. Whether our opponents want to admit it or not, much of the nations gun control was prompted by these anxieties among political elites
Back way then when I got into the Gun Rights melee, the NAACP and other minorities groups were backing up the Clinton Administration who were pretty vocal about banning guns, how Evil Gun Makers were targeting the Ghetto with cheap guns and how minorities should be gun free…. which was a message that the Ku Klux Klan totally agreed with.
Never forget that Gun Control Laws in the US started and developed to keep the guns from the “undesirables”: They started against the Freed Slaves, Chinese,Irish, Italians, Latinos. Then the powers that be realized that having everybody under control was much more fun and efficient. They do not like that we are fast recovering our rights are not going gently into that night but they are going.