Things can change if enough people will it, gun control, a tightening up of regulations can effect a public change of mood. That is a very powerful thing. It needs political courage to start the ball rolling.
Those are all valid but guns are part of America's culture. It will be very hard to change an entire countries culture. Gun ownership transcends all types of groups. Democrats, Republicans, all races, males, and females. ect. own guns in this country. A mass shooting and killing of little children is not enough to even get real gun control laws to be pass on a national level, and people still think guns will be banned.
Again, the only question I have is, "How are you going to disarm over 100 million Americans and remove around 310 million guns from this country?"