Your point has been brought up before. The theory by anti-gun activists is that regardless of those other factors......More Guns = More Gun crime. That is where they hang their hat.
So.....the point they miss, and I think you miss....is that over those 26 years.....whether or not normal people owning guns was a factor in reducing gun crime.....
More Guns in the hands of law abiding people did not increase the gun crime rates...
So over that 26 years.....more Americans own and actually carry guns....17.25 million Americans from about 4 million actually being able to legally carry guns.....and the gun crime rates went still went down.
So the core theory is wrong....More Guns did not = More gun crime.
Now, it is true that various factors made the murder rate go down, more police, smarter police tactics and so on.......but that isn't their argument or their point.......
Also, for one thing........if you are being attacked, and you use a gun to stop the attack....that crime didn't happen to you....
Then, I have actual research from various researchers who state that there is a correlation to decreases in interpersonal crime when more people own and carry guns...for example, there are more home invasions in Britain than here in the U.S....why? When researchers ask criminals in prison, they state they go into empty houses in the U.S. because they don't want to get shot. In Britain, the criminals don't care about people being home, because they don't have guns...and since they don't have guns, they can be tied up and questioned about where their belongings are...