The effect of a gun in the home is not to increase the occupants' safety but to greatly increase the risk of the gun-owner, family members or acquaintances dying from a gun shot:
http://www.bradycampaign.org/risks-of-having-a-gun-in-the-home This increased risk of homicide and suicide in households with guns occurs regardless of storage practice, type of gun or number of guns in the home:
http://aje.oxfordjournals.org/content/160/10/929.full
And the General Social Survey finds very clear trends of declining gun-ownership and households with guns in the US, with the percentage of households with guns dropping from 50.4% in 1977 to 31% in 2014, and a similar decline in the percentage of adults in households with guns. The largest percentage of survey respondents who reported owning at least one gun was in 1985, amounting to less than one-third of respondents (30.5%); this figure has shrunk to 22.4% in 2014 (which is slightly up from 2010):
http://www.norc.org/PDFs/GSS Reports/GSS_Trends in Gun Ownership_US_1972-2014.pdf
I don't know how else to interpret these data than that Americans are becoming wiser on the injudiciousness of owning guns. There is certainly no basis for interpreting these figures as showing Americans becoming less wise regarding gun ownership, as there are no benefits to gun ownership.
Americans' progress in learning this is slow, all too slow, and Americans are far behind other countries in acquiring this wisdom, but it seems to be steady progress nevertheless.