Good, the more gun owners we have the less chance they can ban.
Who told you that?
Why are the anti-gun organizations pushing so hard to ban the AR-15 and all other "assault weapon" rifles?
Answer: Because the AR-15 is the most widely owned sporting rifle in the US. Ban assault weapons, and you ban a larger percentage of long guns in private hands than you would any other rifle.
This, even though rifles, and in particular AR-15s/Assault Weapons, account for an insignificant proportion of violent crimes in the nation.
So, your theory, feeling, belief, "fact" holds no water. Even though the courts have identified that "weapons in common use" helps classify it as protected under 2A, large numbers also make them a larger target for bans.
Since pistols represent the highest proportion of firearms used criminally, why aren't they also targeted for bans?
Answer: They were -- when semi-autos first became popular. The lie was "Only gang members, drug dealers and other criminals carry semi-autos with 10-15 round mags." That became untrue as more and more private buyers opted for semi -auto pistols for home defense. They really lost the argument when law enforcement agencies started issuing them.
Basically, they tried and lost the semi-auto pistol ban. Now they focus on scary "weapons of war" using fear and ignorance to have their agenda passed.