You and Calicamper want more controls where exactly?
Since the 1900's, we have put some restrictions in place on the 2nd Amendment (mostly to do with fully auto firearms and pistol licensing and open carry), which is why more than a few are reluctant to allow for any more. You ask how people and groups, like the NRA, are capable of becoming so stubborn to changes/revisions to gun laws; it's because there is a mentality exhibited by some that if they take away certain firearms/permissions, they can then take away others...a slippery slope.
The reality is gun violence, unlike the car analogy you keep clinging to, is not an accident issue...it's a crime issue. One has to do with inadvertent deaths the other has to do with intentional homicide/assault. Getting illegal firearms off the street is one thing we can all agree on. Saying that we need to put further burdens on the law-abiding population is where you'll start to meet staunch resistance.
You and others focus on negligent use/behavior by certain firearm owners, or the lack of certification and training. The overwhelming majority of gun-related homicides are caused by pistols in the hands of repeat offenders....if you and others were truly serious about reducing gun violence, you would focus your advocacy efforts on restrictive pistol permitting/registration (which already happens to a large degree in many states) and on increasing punishment for criminals across the board.
I'm not saying that I would fully embrace such an approach (at least not additional pistol licensing, since my state makes it tough enough as it is), but logically speaking, those should be your areas of focus if you were truly in favor of reducing gun violence. And yet all I hear from you and others is that we need to increase the licensing, restrictions, burdens for everyone and every weapon.
Many gun/injuries are accidental. If the car/gun analogy is to be used, we must admit cars are are much more necessary to every day life than guns. So not a good analogy.