An inter-generational conspiracy to disarm the population? Extraordinary claims require extraordinary evidence.
There is no need for an inter-generational conspiracy to disarm the population, they could enact laws in a few months to do such a thing, no need to draw it out and never see the results due to dying of old age.
I believe it is more because society is changing and violence is becoming less acceptable and the need for firearms is reducing due to urbanisation. The media of the day seem to make people unnecessarily fearful of the world out there, and distrusting of anyone holding a position of power.