Why is it so difficult to change an outdated constitution?
Seriously how can some association have so much say in gun control.
Just like our constitution most changes would require a vote by the people, over there changes just don't go through, like here (eg becoming a republic).
Over there they will not give up one right that their constitution offords them, especially the right to bare arms
As to what power congress etc have is a mute point as none of them are prepared to take the gun lobbies on. Because like over here pollies want to keep their jobs, it's all about being a position of power and not losing it
And on your final point well that is again like here it's all about $$$$$$$$$$$$$$$ and how much they give to get people elected