One reason the second ammendment is still in place:

The ammendment when added to the constitution was very viable as the people of the nation were reluctant to relinquish thier right to defend themselves.

Defence including that from thier own government if nessesary; but, also against the any foriegn power as well as the native population and or any one intending them harm.

Sufficient means for any sort of law enforcement to be involved in the equation on the American frontier did'nt even exist but by the "self initiated" ,in any large scale format until the 1920s or there abouts.

Law enforcement response times have gradually increased over the years, yet the vast majority of rual Americans still own and maintain firearms for the purposes of hunting and or self defence. They do so for a variety of reasons, traddition, poor hope of help from emergency responders due to remote locations etc etc.

Self sufficiency has allways been an American rual tradditional pride.

Police in many rual areas cannot repond to emergencies for sometimes upwards of 2-4 hours if at all.

Quite naturally these people have a lot of vested intrest in protecting thier right to protect themselves and are amongst the many forces influencing the Surpreme Courts discission to up hold the law of our United States.

It all comes down to protecting our individual freedom to the rights of "life liberty and the pursuit of happiness" for "ourselves and our posterity".