You've largely got the lay of the land correct. I'd add:
These two "religions" are irreconcilable; the pro-gun control group has, since at least the '70s when I started closely following this and being an anti-gun control activist, made it crystal clear that many of them will not be satisfied until they've taken all of our guns (or nearly so, e.g. the over and under shotgun class like Biden, what e.g. the U.K. has devolved to at the same time they've reversed the trend since the 13th Century of decreasing interpersonal violence). In return, we've made it clear that we know our 20th Century history, if they get very far in this, we'll kill them, wholesale and retail. No common ground possible there.
Second, this is part of a larger cultural war. We need look no further than now President Obama saying in 2008:
You go into these small towns in Pennsylvania and, like a lot of small towns in the Midwest, the jobs have been gone now for 25 years and nothing's replaced them. And they fell through the Clinton administration, and the Bush administration, and each successive administration has said that somehow these communities are gonna regenerate and they have not.
And it's not surprising then they get bitter, they cling to guns or religion or antipathy toward people who aren't like them or anti-immigrant sentiment or anti-trade sentiment as a way to explain their frustrations.
Third, there have been some major changes in gun owning demographics, purposes and the like, part of what some call Gun Culture 2.0, and it really started becoming a thing post-9/11, when the Federal government made it clear we were on our own. The other part is a rapidly graying society as the Baby Boomers reached middle age and now retirement age. For whatever reasons, a very large fraction of them are turning to guns for self-protection, e.g. the vast majority of people in my 2008 Missouri CCW class were obviously middle aged or older.
There's also been some massive changes on the ground: starting in 1987, "shall issue" or better concealed carry regimes have swept the nation, such that they hold in all but 7 states, and cover 72.6% of the population. Issued licences are now growing by more than a million per year, the numbers are astounding, and on a percentage basis have reached 5-10% of the population in shall issue states.
In the same period, "Constitutional Carry", i.e. no permit required, went from 1 state, Vermont (which simply never restricted it post-Civil War) to 10, with 2 being added in the last month or so, and perhaps more to come this year. That's now 7.2% of the above percentage. See this with nice graphs here: http://onlygunsandmoney.blogspot.com/2016/04/every-picture-t... (although I'd add that DC, MD, and NJ are de facto no issue states (for a demonstrated serious need, MD may issue for the duration of the threat), even if the law allows it; also, many local units of CA, MA and NY are de facto shall issue or thereabouts).